It’s more than calories: finding convergence between nutrition, food systems and environmental sustainability

Food, for me, lies at the core of the environmental-social-economic nexus: a basic human necessity which both relies on, and contributes to natural resource pressures. Agriculture is the largest consumer of global freshwater supplies (accounting for 70-80% of consumption); accounts for half of global habitable land (as shown in the graphic below); and is responsible for roughly one-quarter of global greenhouse gas (GHG) emissions. The growing scarcity of these natural resources, combined with impacts of climatic change, population growth and economic growth (which drive a change in dietary patterns) combine to create the so-called ‘perfect storm’ of the future.


Coming from an environmental background (my BSc was in Environmental Geoscience, and my MSc in Carbon Management at Edinburgh), my primary concern was initially focused on the ecological impact of global agriculture—on how to reduce and mitigate the impact of the food system on environmental degradation. This goal, however, completely excludes a human dimension or motivation for change, neglecting to acknowledge the key purpose of food—to provide nourishment.

This nutritional challenge is also one we are failing to meet at the global level: 815 million (one-in-nine) people were undernourished in 2016; an estimated one billion people suffer from protein deficiency; one-third of under-5s are born stunted (low height-for-age); more than two billion suffer from micronutrient deficiencies (also known as ‘hidden hunger’); and paradoxically two billion adults are classified as overweight or obese, with strong links to an alarming rise in the prevalence of non-communicable diseases (NCDs) such as type-II diabetes and heart disease. This challenge exists across countries of all income levels, high-income nations included.

prevalence-of-undernourishment (1)


If our aim is to fulfil the basic, classic definition of sustainability, to “meet the demands of the current generation without sacrificing the opportunities of future generations”, we need to achieve both of these dimensions—meeting the nutritional demands of everyone in the current generation whilst also reducing environmental impacts for future generations. Focusing on only one of these dimensions is insufficient: if you fail in either, you fail in sustainability. The emphasis of my PhD work has therefore evolved to find the sweet spot where both health and environment converge.

The standard metric for tracking progress on global nutrition and related health outcomes—caloric intake—is now outdated. As the fundamental measure used to track progress on ending ‘hunger’ within the previous Millennium Development Goals (MDGs), it’s not surprising that most countries have tracked nutritional progress based on their ability to produce enough calories for their population. The updated Sustainable Development Goals (SDGs), which have a target date of 2030 broaden this goal to ending all forms of nutrition. This effectively extends the targets and measures we need to include protein, fat, micronutrients, amino acids, obesity and diet-related non-communicable diseases (NDCs). Many high-income countries also struggle with many of these nutritional challenges—the SDGs are therefore a truly global health challenge.

How do we develop a global food system which nourishes (not just feeds) everyone in an environmentally sustainable way? The first step—and one I’m trying to address in my research—is understanding what the food system currently looks like across these various nutritional elements. We understand how many calories we produce, how much we feed to animals, where it flows through the supply chain, and how much is lost/wasted fairly well. However, our understanding of these pathways for other nutrients essential for health is comparatively poor.

The next step is to estimate how this demand and supply will change in the future through various socioeconomic and environmental drivers—this is an area we know even less about. Once we have developed a picture of what our current system and future demands look like, we can begin to analyse what levers or hotspots within the food system we can target to make it more environmentally sustainable, achieving the right balance in nutritional components necessary for human health.


Data-Debunking Trump’s Paris Agreement Claims

[Disclaimer: the visuals used in this post were made using OurWorldInData‘s grapher tool. I would like to thank Max and the team for allowing me to use them in my own writings. OurWorldInData is a web publication which presents interactive visualisations of development and how the world is changing, and well worth exploring. You can interact, engage and explore all of the data visualisations used in this post by clicking on the image]

Donald Trump recently announced that the United States would be withdrawing from the Paris Accord- the international treaty signed to address global climate change. The White House have released his statement on the Paris Climate Accord, available here. In this statement, Trump made a number of bold claims about the relative fairness, economic impact and share of responsibility. In truth, the real figures prove many of his statements to be factually incorrect. In this blog post, I have looked at the real data behind Trumps’ key claims (which are quoted in bold).

Before we pick through Trump’s statement, it’s worth giving a quick outline of the Paris Agreement process. The Paris Agreement took a different approach from prior climate negotiations (such as the Kyoto Protocol). Prior to the agreement, countries were asked to submit their so-called “Intended Nationally Determined Contribution” (INDC). This INDC process essentially asked countries to decide and pledge their own commitment to what they thought they could achieve over the medium and long-term in terms of greenhouse gas emissions reductions. It gave countries autonomy for their own targets. This was a stark contrast to previous negotiations where expected contributions from developed countries were decided for them.

“The United States will cease all implementation of the non-binding Paris Accord and the draconian financial and economic burdens the agreement imposes on our country. This includes ending the implementation of the nationally determined contribution and, very importantly, the Green Climate Fund which is costing the United States a vast fortune.”

There are two economic impacts we have to look at here. The first is economic investment that countries have to contribute to meet their respective climate targets (or “nationally determined contribution”). This is essentially the economic cost of investing in a transition to low-carbon technologies (such as renewable energy). In the chart below, we have mapped global investment in renewable technologies through time, aggregated by region or country. In 2015, the US accounted for 15 percent of global investments. In comparison, China accounted for 36 percent- about the same as the US, Europe and India combined.

However, comparing investments in absolute terms doesn’t tell the complete story. It skews focus towards larger economies; we might expect that large economies will also invest more. If we are comparing countries in terms of who is contributing their ‘share’, perhaps a more appropriate comparison is to normalise these figures as the percentage of a country’s gross domestic product (GDP). In the second chart below, we have presented 2015 renewable investments as a percentage of a country’s GDP. The United States invested only 0.1 percent- nine times less than China, and five times less than India. This is not exactly a “draconian financial and economic burden”.



advanced economies have formally agreed to jointly mobilize USD 100 billion per year by 2020, from a variety of sources, to address the pressing mitigation and adaptation needs of developing countries. The other financial cost to the United States is its contribution to the Green Climate Fund (GCF). The Green Climate Fund was set up as a financial mechanism to support developing countries, for both mitigation (for example, supporting investment mechanisms for clean energy) and adaptation (developing countries are likely to be disproportionately affected by negative climate change impacts). Advanced economies have formally agreed to jointly invest 100 billion USD per year by 2020 to the GCF.

To date (2017), only 10 billion USD have been pledged, only one-tenth of the amount which is to be mobilised by 2020 (so you can see why grievances within the GCF might lie with developing, rather than developed countries). The United States have pledged they will contribute three billion to the fund (although to date have only mobilised one billion). In the chart below, we have shown the relative GCF pledges across advanced economies, normalised to the amount pledged per capita of the donor country. The US has pledged 9.41 US$ per capita. Sorted in order of per capita contribution, the United States comes in 11th place; very low for the world’s largest economy. By my calculations, if the US contributed its 3 billion US$ to the fund, this would amount to 0.02% of its GDP.[ref]According to World Bank figures, the USA’s GDP in 2015 was 17.95 trillion USD. 3 billion USD as a percentage of its GDP is approximately 0.02%. World Bank figures available online.[/ref] Not exactly the “vast fortune” Trump claims it to be.


“China will be allowed to build hundreds of additional coal plants.  So we can’t build the plants, but they can, according to this agreement.”

It is true that within the Paris Agreement, China has not set a specific date or greenhouse gas reduction target. Instead, like India, it has set a carbon intensity target. Carbon intensity measures the amount of carbon dioxide emitted to produce one unit of GDP. In committing to reducing carbon intensity, both China and India pledged to grow their economies, but in a more carbon-efficient way.

So, technically speaking, neither countries have specific restrictions on coal production. Will China be building hundreds of additional coal plants? First, remember back to our initial charts on renewables investment: China invests more in renewable energy than North America, Europe and India combined. As a percentage of its GDP, it invests nine times more than the United States. China has strongly committed to an infrastructural transition to a lower-carbon economy.

China’s coal consumption has grown rapidly in recent decades. In the chart below we have plotted its annual coal consumption and production trends from 1965-2015. As we see- and it is a trend that has surprised many- that China’s coal consumption appears to have peaked back in 2013. In the past three years, its consumption has continued to drop. This had such a large impact on global coal projections that the International Energy Agency (IEA) more than halved its predictions for global coal consumption in 2040 in its 2016 World Energy Outlook 2016 Report.

In fact, despite not having a bound commitment within the Paris agreement, China has outlined a mandatory reduction target in its 13th five-year-plan (2016-2020). It has pledged to produce no more than 58 percent of its total energy consumption from coal- a six percent reduction on coal’s share in 2015.


“India will be allowed to double its coal production by 2020.  Think of it:  India can double their coal production.”

Like China, India has not committed to an absolute greenhouse gas cap or reduction target within the Paris agreement. Instead, it has set a carbon intensity target to reduce the emissions intensity of its GDP by 33 to 35 percent by 2030 from 2005 levels. With the highest absolute number of people living in extreme poverty, and around one-fifth as a share of the total population, economic growth and poverty alleviation is an obvious priority for India. It has therefore committed to continuing development, but in an increasingly lower-carbon way.

It’s true that India will increase its coal production in the coming years. There are two points to note on this. Firstly, although India will increase its coal production from today’s levels, it continues to show strong commitment to low-carbon growth. Relative to its GDP, India invests five times as much as the United States in renewables. At the end of 2016 it raised its ambition to produce 57 percent of electricity from non-fossil fuel sources by 2027 (in the Paris agreement, it set a target of 40 percent by 2030). Last month India responded to falling solar prices by cancelling 14 gigawatts (GW) of planned coal installations.

The second point refers to the large inequalities with exist between the United States’ and India’s CO2 contribution. In the map below we have plotted the average per capita CO2 emissions by country. In 2014 India’s per capita emissions were less than two tonnes; the USA’s more than sixteen tonnes (more than eight times as much). Whilst Trump talks about doubling coal production by 2020, the truth is that India’s per capita contribution would still be multiples lower than that of the United States. Note that whilst Trump has singled out India here, the same applies for many of the world’s low to middle-income countries.

In the second chart below we have plotted the hypothetical global CO2 emissions if everyone in the world adopted the per capita emissions of a given country. If everyone in the world had the same footprint as the average Indian, global emissions would be about one-third of actual levels in 2014. In contrast, if everyone lived like the average US citizen, global emissions would be more than three times higher than they are currently.


“I cannot in good conscience support a deal that punishes the United States — which is what it does -– the world’s leader in environmental protection, while imposing no meaningful obligations on the world’s leading polluters.”

There is no metric related to greenhouse gas emissions whereby the United States is not a leading polluter (or is a world leader in environmental protection). As we have shown above in terms of per capita CO2 emissions, the United States is one of the world’s highest (representing large global inequalities, even relative to other high-income economies).

If we look at historical responsibility for CO2 emissions (the amount of CO2 which has cumulatively been emitted over time), the United States is the world’s largest contributor (even when European Union countries are counted collectively). The USA has more than double the cumulative emissions of China. Cumulative emissions are shown in the chart below (you can press ‘play’ to see this change through time).

However, even if we forget about historical responsibility and focus only on current levels of emissions, the USA is the world’s second largest national emitter. Total annual emissions across the world are shown in the second map below. The United States is second only to China, accounting for around 15 percent of global emissions.

As we have discussed above- many of the world’s other leading polluters (even on a national, not per capita basis) such as China and India are showing even greater ambition and commitment than their obligations state within the Paris agreement.



“In short, the agreement doesn’t eliminate coal jobs, it just transfers those jobs out of America and the United States, and ships them to foreign countries.”

Trump may be worried about a decline in jobs with the fossil fuel industry, but the USA has seen dramatic growth in employment in the renewables industry in recent years. Employment within the solar and wind energy industry is reported to be growing at 12 times the rate of the USA’s economy, with jobs in these industries sustainaing a compound annual growth rate (CAGR) of nearly 6% since 2012.

However, this mention of trade and transfer raises another important point which actually works to the USA’s advantage within the Paris agreement: the issue of embedded emissions. National accounts and targets within the Paris agreement are reported based on CO2 production emissions. This accounting method is also sometimes referred to as “territorial-based” emissions because it reports emissions as those emitted within a country’s given geographical boundaries. As a result, this method takes no account of emissions which may be imported or exported in the form of traded goods. “Consumption-based” accounting adjusts CO2 emissions for this trade of emissions and more accurately reflects the emissions necessary to support a given country’s way of living.

What does a global map of traded CO2 emissions look like? Below we see emissions embedded in trade in 2004 (in million tonnes per year); the thickness of the arrow is representative of the size of traded CO2. This shows an important East-to-West relation, with large exports from Asia and Eastern Europe into Western Europe and North America.

In other words: some of the CO2 produced (and reported) in emission records of Asian and Eastern European countries is for the production of goods consumed in Western Europe and North America. A study conducted by Davis and Caldeira in 2010 estimated that if we switched to a consumption-based reporting system (which corrects for this trade), the annual CO2 emissions of the US would increase by 10% and China’s emissions would decrease by 22%.

In other words, from a CO2 perspective, developing countries are not only held responsible for their own emissions, but also have to account for the emissions embedded in goods sold to the United States and other high-income countries. If we accounted for this fact, global inequalities in emissions would be even greater.

CO2 emission flows from embedded carbon in global trade (Davis and Caldeira, 2010)

Heated debate: why was it so hard to get a global climate deal?

Disclaimer: the visuals used in this post were made using OurWorldInData‘s grapher tool. I would like to thank Max and the team for allowing me to use them in my own writings. OurWorldInData is a web publication which presents interactive visualisations of development and how the world is changing, and well worth exploring. You can interact, engage and explore all of the data visualisations used in this post by clicking on the image.

In 2015, members of the United Nations (UN) finally managed to agree on a new deal to address global climate change. While this meeting in Paris was seen by many as an important victory, it marked a long-fought stalemate in global negotiations—a dialogue which has spanned several decades of heated debate. So, why has it been so hard to reach a global plan on how to reduce our carbon emissions?

Before trying to unravel the complications in international negotiations, it’s important to note that carbon dioxide (CO2) emissions have historically been strongly linked to economic growth and human development. Below, I have plotted the relationship between national average GDP and per capita CO2 emissions (which, by clicking on it, you can explore through time). Broadly speaking, GDP growth has typically been driven by increased energy provision and industrialisation, with an unintended consequence of increased CO2 emissions. This economic-CO2 link has two important implications:

  • countries still undergoing development (and attempting to alleviate poverty) are likely to continue growth in their CO2 emissions;
  • nations may perceive targets to reduce their carbon emissions as putting themselves at an economic disadvantage relative to countries who have lesser or no reduction targets.


This has ultimately led to a distinct divide in international negotiations between developed and developing nations, with heated debate as to how the responsibility of mitigating climate change should be shared. The reasoning for this rift can be explained in three key visuals.

Who is responsible for the carbon dioxide (CO2) that has accumulated to date?
If we extend our timeline back to 1750 and total up how much CO2 each country has emitted to date, we calculate each nation’s ‘cumulative emissions’. The question ‘who is responsible for the historical contribution to CO2 concentrations in the atmosphere?’ could be reworded as ‘who has emitted the most CO2 to date?’.

In the chart below, we have plotted the cumulative emissions of each nation through time from the industrial revolution in 1750. Europe, shortly followed by North America, has been producing CO2 over this full time period. Other regions—Latin America, Asia and Africa—started contributing to global CO2 emissions much later (largely contained to the 20th and 21st centuries). Fast-forward to the accumulated totals we see today, the USA is the largest cumulative contributor (with more than double the cumulative emissions of China). As a combined emitter, the EU also dominates. Note that you can view the cumulative visual in absolute or relative terms.

From the standpoint of developing nations: the earliest industrialisers in Europe and North America hold the largest responsibility for CO2 emissions to date.

cumulative-co2-million-tonnes 2014

Which nations currently emit the most CO2?
If we forget the accumulation aspect from historical emissions, and focus on who currently emits the most CO2, does that shift the share of responsibility? Below we can view annual emissions by country through time. Note that you can choose to view any country in a line or map visual. In reflection of the cumulative chart we explored above, we can see that the annual trends of European and North American nations have grown much earlier than in other regions.

However, emissions from a number of growing economies have been increasing rapidly over the last few decades. Fast-forwarding to annual emissions in 2014, we can see that a number of low-to-middle income nations are now within the top global emitters. In fact, China is now the largest emitter, followed by (in order) the USA, EU-28, India, Russia, Indonesia, Brazil, Japan, Canada and Mexico. Note that a number of nations who are already top emitters are likely to continue to increase emissions as they undergo necessary development.

This brings us to the argument of developed nations: to effectively address climate change, all of the top emitters have to take their share in carbon reduction, including nations still undergoing rapid development.


How much CO2 do we emit per person?
There is a key drawback to the measure of total national emissions: it takes no account of population size. China is currently the world’s largest emitter, but since it also has the largest population, all being equal we would expect this to be the case. To make a fair comparison of contributions, we have to therefore compare emissions in terms of CO2 emitted per person.

Below we can compare CO2 emissions per capita through time since 1950 (this data is probably most interesting when viewed in map mode). Again, if we cycle through time, we see that per capita emissions in most countries have continued to increase in line with development. However, if we look at the distribution of per capita emissions in 2014, large global inequalities remain. Note that carbon dioxide is not the only greenhouse gas which contributes to climate change—nitrous oxide and methane are not included here. If these gases were included, the global inequalities would be even higher.

With a few exceptions, there is an important north-divide in terms of per capita emissions. Most nations across Sub-Saharan Africa, South America and South Asia have per capita emissions below five tonnes per year (many with less than 1-2 tonnes). This contrasts with the global north where emissions are typically above five tonnes (with North America above 15 tonnes). The largest emitter- Qatar- has per capita emissions of 50 tonnes per year (1243 times that of Chad, the lowest emitter).

Smaller capita emissions across low- and middle-income nations is largely a reflection of lower levels of prosperity—as these nations to develop, we would expect their per capita emissions to grow.


The great divide
So, how do these three visualisations explain the international climate divide?
From the perspective of many developed nations: some developing economies—namely China and India—are now some of the largest global CO2 emitters. As other nations also continue to develop, more transitioning economies are likely to enter the top rankings. To tackle climate change, all countries must therefore reduce emissions. If they fail to, the efforts of developed nations will be diluted to very little.

From the perspective of many developing nations: the responsibility of historical and cumulative CO2 emissions largely lies with high-income economies who have had a long history of industrialisation and development. This opportunity for development without carbon restrictions is now reflected in the large economic and lifestyle inequalities between the global north and south (as reflected in today’s differences in per capita emissions). Placing carbon reduction targets on these nations would act as an unfair barrier to development and poverty alleviation.

Seeing the World as it is, with Hans Rosling

Last year we said goodbye to David MacKay, a guy whose unique approach to sustainability, energy and environment has been a key influencer in the work I do today. It was with tremendous sadness that 2017 brings the loss of another inspiration of mine: Hans Rosling. While working in slightly different fields, the similarities between the two—both in life and death—are not lost on me.

Both had an overwhelming and infectious love of statistics, especially high-level, big-picture data. However, understanding statistics was never enough—the real joy came in communicating stats in a way that anyone could understand. The magic of the data was somehow lost if that feeling of enlightenment—which often accompanies the realisation of an unseen trend—wasn’t shared. While David worked on big-picture renewable energy numbers, Hans was more concerned with global development progress—poverty, inequality, education and health. I now seem to work at the fringes of both of these fields; big data at the blended seam where human development meets environmental sustainability. The influential mix of these two figures are to blame. I owe them both a lot.

The pairs’ parallels in mindset seemed to extend to death, with both losing a battle with cancer before their time. David was only 48 years old. Hans had an extra 20 years, dying at the age of 68, yet by today’s standards this still seems premature. It’s somewhat ironic that a guy who spent so much of his life showing others how far global health and life expectancy had progressed, was lost too soon. Nonetheless, as a master of health data, I’m sure Hans would argue that his case was not beyond what one would expect from statistical expectations. It makes me wonder whether the expected question of “why me?” ever crossed his mind. I suspect not.

It never ceases to amaze me how small influencers (usually oblivious to their true impact) can have such a dramatic impact on shaping the lives they touch. I stumbled upon Hans’s work at just the right time. Finishing my undergraduate degree in Environmental Geoscience, I was left feeling somewhat helpless and emotionally exhausted. I don’t think this feeling is uncommon amongst environmental students. Don’t get me wrong, I loved my degree subject—I don’t think I’ll ever lose the curiosity that led me to study the complexity of planetary systems in the first place. But it can be a hollow field to work in at times. Five years of natural science where human development was largely absent, and only featured in discussions over our devastating impact on environmental decline. The tensions between human impact and planetary systems are magnified tenfold, until it’s unavoidable to see the world any other way than: humanity versus environment. It seemed like a depressing fate: confined to a career of fighting progress on the environment’s behalf. Not only were we failing at sustainability, but social progress was stalling. Even David MacKay and his breathtaking work could offer little in the way of optimism.


If you’ve watched any of Hans Rosling’s work, you’ll understand how my perspective flipped from then on. I’ve yet to find anyone who can present such a truly fact-based vision of the world with unbounding energy, clarity and hilarity. He had a unique ability to make you feel both stupid and enlightened at the same time, yet love him even more for doing so. People often talk about a profound moment when everything seems to ‘click’ and fall into place: for me, it was seeing into the mind of Hans Rosling. It’s not until you take that important step back and look at the picture in full that you see how far the world has come. Almost any statistic upon which you would global progress—percentage of people below the poverty line; child mortality rates; life expectancy; number of children in education; energy access rates; adult literacy rates—are better than they ever have been. Next year, things will most likely be a little better than they are now. And, the next year the same will occur. That in itself, once you see it in the global datasets than Hans presents (and are free to explore at Gapminder here), is worth reflecting on.

This was a real eye-opener for me, and an inflection point to where I am today—still working in environmental sustainability but always with a view to human development. It’s no longer a case of environment or progress. It’s about ensuring and sustaining progress (because the world will continue to do so, regardless) in the most sustainable way we can.

It saddened me to hear that Hans was often jaded and doubtful of whether he had really made any true impact. In his mind, despite many years of trying to present a fact-based view of the world, so many remain ignorant to how the global development landscape really is. True, many will never have watched his videos or looked at the statistics. But for those who have, the impact can be transformative, and through this sharing of the flame, his legacy can continue to drive progress. Every one of my university students has been introduced to his work; he features in nearly all of my lectures and teachings. I’ve seen the influence first-hand. There are few greater pleasures than hearing the giggles from students as they watch Hans chase statistical bubbles across the stage; see that glint of revelation as they realise their view of the world had been wrong all along; that transformative moment when they grasp that the truth is there to see when you take a step back to see it in full. This is how we continue to build a fact-based view of the world, and a legacy that Hans deserves.

I’ll leave you with one of my favourite clips of his. It also happens to be one of the most relevant to the essential blend of environmental sustainability and global development. Note: I was once probably one of the ignorant environmental students he references in this talk. Thank you, Hans, for helping me to see the bigger picture. You will be sadly missed, but never forgotten.


Breath: it’s time to rationalise respiration in livestock emissions

The contribution of livestock to climate change is now well-established, and showing growing awareness in the average consumer. The FAO estimates that livestock alone contribute approximately 15-20% of global greenhouse gas (GHG) emissions. That’s a lot, especially when we consider that in contrast to other key contributors such as energy and road transport, there are fewer “clean” options for mitigation (besides eating less meat, of course).

As someone who spends their days researching and analysing the interactions between agriculture, nutrition and sustainability, I’ve come to know the relative carbon intensities of different foods by heart. Around three kilograms of CO2e (carbon dioxide equivalents—the measure of GHG emissions) are emitted for every kilogram of chicken meat; pork is a little worse at 4.5-5 kilograms; beef worse still, ranging anywhere from 12-30 kilograms; and in some systems, lamb comes out worst at 14+ kilograms per kilo [shown a little further down]. I’ve gotten used to quoting these numbers for years, and perhaps out of habit (or ignorance?) taken the methodologies by which they’re calculated for granted. They were, after all, set by the UN’s Food and Agriculture Organisation (FAO).

It wasn’t until I had to carry out a carbon intensity assessment for a food product myself, that I started to question whether these numbers capture the full picture of the global impact of livestock. I’m Sustainability and Business Development Manager for 3f bio, a spin-out company developing a novel and patented zero-waste technology for the production of Food, Fuel and Feed. The technology aims to make the meat-free food product mycoprotein (you may know it more commonly by its brand name Quorn™) through integration within existing biorefineries which already produce bioethanol (fuel) and animal feed (DDGS). Long story short: we’re developing a zero-waste process which can make healthy, low-cost, sustainable protein.

So I crunched the numbers on the GHG emissions, and our mycoprotein comes out at about 1.05kg/kg (shown below versus other protein). A good result: much lower-carbon than meat alternatives, and significant reductions on the existing process for mycoprotein production. However, there was still one key difference between the methodology for calculating our emissions, and that of livestock products. We included emissions from respiration in our estimates; a source of emissions left out of livestock numbers.

co2-intensity-imagesRespiration (i.e. breathing) isn’t simply an oversight—we didn’t just happen to forget that livestock breath out carbon dioxide. The FAO explicitly excludes respiration emissions on the basis that:
Respiration by livestock is not a net source of CO2…. Emissions from livestock respiration are part of a rapidly cycling biological system, where the plant matter consumed was itself created through the conversion of atmospheric CO2 into organic compounds. Since the emitted and absorbed quantities are considered to be equivalent, livestock respiration is not considered to be a net source under the Kyoto Protocol.

In other words: animals are part of a short cyclic system with the natural environment such that respiration is not a net source of emissions. In practice, this is right. To grow, crops (it could be grass, cereals, pulses—any crop an animal would eat) essentially capture CO2, removing it from the atmosphere. Then when an animal eats the crop, this CO2 is emitted back to the atmosphere through respiration (breathing). In a balanced natural system, this can continue over and over with no change in atmospheric emissions. Crop captures CO2 –> animal eats crop –> animal exhales CO2 –>crop captures CO2 –> animal eats crop –> animal exhales CO2. And repeat.

So it’s true: in a balanced biological system, respiration is not a net source of emissions. And since the FAO sets the guidelines for how to report on agricultural emissions, no one includes respiration in livestock footprints. But is there a valid case for us doing so?

There’s one fundamental driver of the need to have a focus on environmental sustainability at all: the very fact that humans are rapidly shifting Earth’s biological systems out of equilibrium. If our systems were in equilibrium—which is the rationale for not including respiration in our calculations—then there’d actually be no need for us to discuss climate change at all. The rapid rate of change through which we are altering our biological systems (which includes the carbon cycle) means that they are now out of balance.

Now, going back to the assessment that triggered this discussion in the first place: calculating the footprint of mycoprotein (a type of fungi). The very nature of the process is almost identical to that of livestock. It works like this: we feed a carbohydrate-rich crop into a fermenter, add some nutrients and oxygen –> fungi/mycoprotein grows –> as it grows, it respires–> this CO2 is emitted to the atmosphere. There’s actually very little difference between this and a livestock system; the only difference being that mycoprotein is grown in a fermenter rather than a barn or field, and the CO2 is emitted through a pipe rather than an animal’s mouth. In both processes, the CO2 was initially captured by the feed crop as part of a cyclic loop.

We included respiration in our calculations, because it didn’t make sense—and there is no credible case—for us not to. The process essentially emits CO2 through a pipe/vent/column to the atmosphere. It is therefore a source of atmospheric CO2 emissions. When compared in this way, it throws up the question of whether we should be doing the same for livestock.

Just how much of a difference would respiration make to these numbers? I crunched some of the numbers on respiration emissions based on published respiration rates[1], and animal growth/lifespan figures. You can see the end result below as dashed columns. For mycoprotein figures, I have subtracted respiration emissions to show the difference it makes.

[I should note that I’m providing these as an estimate only—there can be variability based on factors such as the lifespan and size of an animal, and its feed intake. Although not perfect, they should still give a feel for the magnitude of difference].


Makes a big difference, right? Some studies [although they have received some criticism on underlying figures, and are somewhat ideologically motivated] estimate that with respiration emissions, livestock would account for 51% of total global GHG emissions[2]. I suspect that’s not wholly accurate, but it’s still significantly larger than the figures we currently report.

However, the purpose of this discussion wasn’t to try to demonstrate or emphasise how bad or carbon-intensive meat is. With or without respiration emissions, it’s already obvious. It was in fact to raise a wider question of how we account for our GHG sources and sinks. As I mentioned above, we’ve shifted our natural systems—including the carbon cycle—out of balance. Now, in the Paris climate agreement, the world has [I should technically say “will” because it hasn’t come into force yet] pledged to restore this balance in the carbon cycle. In technical terms, we’ve pledged to achieve “net-zero” emissions. All this means is that our sources and sinks of GHGs balance i.e. the amount of GHGs we emit is exactly the same as the amount that the Earth’s natural systems can capture. Theoretically, if these balance then GHGs do not accumulate in the atmosphere.

What’s fundamental in ensuring that our sources and sinks balance? Knowing what they are and how much they contribute. There’s an old business mantra: “you can’t manage what you can’t measure”, and it lies at the core of what we’re trying to do. If you’re not measuring your sources and sinks, how will you ever be able to track progress in ensuring they balance?

The discussion around livestock respiration has been closed for a while now. But perhaps it’s time (considering the Paris commitment that the world is signing on to), to open it back up again. Yet it should be done through an intent on furthering understanding and progress rather than an underlying agenda to prove or disprove how bad/good our livestock systems are. It’s easy for such discussions to be taken over by groups at either extremes of the spectrum. The end result is usually a drowning out of voices in the middle, until everyone loses patience and we end up no further forward than when we started.

[1] Pedersen, S., Blanes-Vidal, V., Jørgensen, H., Chwalibog, A., Haeussermann, A., Heetkamp, M.J.W. and Aarnink, A.J.A., 2008. Carbon dioxide production in animal houses: A literature review. Agricultural Engineering International: CIGR Journal.


Can UK Climate Policy Weather the Closure of DECC?

In periods of political turmoil or instability, priorities tend to become even more short-term focused than usual. Slow developing, or long term issues inevitably take a back-seat to more immediate concerns. It’s no wonder then that significant concern has been raised about the UK’s long-term commitment to climate change (amongst other environmental sustainability issues) following the Brexit vote to leave the EU, and appointment of a new governmental cabinet. But just how damaging could these changes be for UK climate and energy policy? Maybe not as much as some predict.

There have been two key changes within Theresa May’s new government—neither of which have received a particularly favourable response from the environmental community. The first was the appointment of Andrea Leadsom as environment secretary. The Conservative “Leave” campaigner is now in charge of the UK’s Department for Environment, Food and Rural Affairs (Defra). With roughly 80% of environmental legislation regulated by the EU, and a strong reliance on the EU for farming subsidies, Defra is likely to be one of the most challenging departments to lead in a post-Brexit UK.

Does Leadsom seem prepared or qualified for such a tough task? I’m afraid I can offer little in the way of optimism on this front. Leadsom’s experience in resolving complex political issues—of which she will encounter again and again during such an extreme transition term—is not reassuring. That’s looking beyond her track record on environmental policy decisions, which includes previously voting against UK climate change targets; voting for the sale of British forestry; and a strong stance in favour of repealing the fox hunting ban. I haven’t found much positivity to soften the blow on this one. All I can offer on this front is that her influence will hopefully only last a few years (which seems long, but is arguably short-term on sustainability and environmental terms). How much damage can she really do over that period?

The potentially more influential change—a decision that could stand much longer than Leadsom—was the abolishment of the UK’s Department for Energy and Climate Change (DECC). This has been merged into a new governmental department: the Department for Business, Energy and Industrial Strategy (BEIS). With the exception of a few, most within the climate change “arena” have met this decision with a high degree of animosity.

In truth, my initial reaction was largely negative—this represents a lack of commitment to climate change; the government are trying to sweep it under another banner; we’re going to fall even further behind on our mitigation targets. But upon some longer reflection, and taking a step back, I’ve slowly came round to the idea that it might not be as bad as it seems—at least, it doesn’t have to be. We could potentially utilise this period of transition to kickstart wider progress than we’ve achieved to date.

How long have we been arguing that our business leaders need to be taking more interest in climate change; that economist need to be heeding the financial risks and opportunities; that climate change strategy needs to be embedded across the spectrum and within a wider strategy network? We make these arguments over and over, because they’re true. Climate change can no longer be seen as a bolt-on consideration; it has to become an integrated part of the bigger picture.

If we want it to, this is a prime opportunity to do just that. Greg Clark has been made head of BEIS. I admit to knowing very little about him, other than the fact that he’s an economist by training and has consistently shown not only a strong awareness of climate change as a threat, but actually shows a pretty rational understanding of its risks. I have a couple of idols that I follow, and those judgement I tend to put a lot of trust in (they’ve yet to let me down)—one of them is Chris Goodall. Hopefully he doesn’t mind me sharing his view on Clark’s appointment—I’ve picked it up from his weekly newsletter [if you don’t currently follow Chris, he has a blog “Carbon Commentary”, which he manages to update much more frequently than mine…]:

Greg Clark was made head of the merged industry and energy departments. Environmentalists moaned about the demotion of low-carbon ambitions. I think this is wrong. Clark seems to be a centrist economist by training (he was a member of the Social Democrats in the late ‘80s and has a PhD in economics). His very tightly organised doctoral thesis (here) shows an openness to non-conventional economic models as opposed to raw free-market ideology. My prediction? Put a trained economist who believes in climate science (which Clark does) into government and a global carbon price will come to the forefront of UK policy. The second focus of an economist will be on the operation of the wholesale electricity market, a major barrier to the development of storage.

Beyond the head of the department itself, the merger offers a prime opportunity to increase the presence of climate change policy across business, economic, and industrial strategy. This is not a complete abolition of climate change leadership—there will still be staff members employed in the role of managing the UK’s climate progress. Can you imagine having a presence at top-level business meetings, economic policy discussions and industrial strategy plans, consistently asking the question “how does this tie into our mitigation targets?” and “how can we further re-align this with our low-carbon energy objectives?”.

Rather than being in isolated department, an integration could offer the chance to weave our climate ambitions into every discussion. Is this not what we’ve been arguing and asking for a long time? Everyone likes to talk about inter- or multi-disciplinarity—it’s essential—but often we shoot ourselves in the foot by putting the barriers up when opportunities to integrate present themselves.

Of course, all of this is hypothetical—I fully acknowledge that this won’t, and is unlikely to, happen by default. I’m not naïve enough to suggest that climate change strategy is going to suddenly become integral to our business and economic planning moving forward. But if we fight hard enough, it could certainly gain a much larger, and more positively-driven presence than it currently has. Either way, we’re left with two options: to forever mourn the loss of DECC, or to try to build something better and more holistic with what has fallen out. The only option which is going to get us anywhere is the latter.

Does the World Have a Protein Problem?

When it comes to sustainability, protein and in particular, animal-based protein is a topic that can get a lot of attention. In a couple of months’ time, I’m about to embark on a PhD looking at how we can sustainably meet our growing global protein demands through to 2050. In other words: how can we ensure everyone has access to a protein-sufficient diet in a way that reduces pressure on our natural environment and resources?

However, a question I’m often asked is “wait…aren’t we all already consuming too much protein?”. It’s a widely-held belief and, as you’ll see below, a perspective that’s often portrayed by some of the world’s leading sustainability think-tanks. So before I start, maybe it’s worth addressing the question: does the world really have a protein problem?

To try to answer this question, I’m going to build upon some analysis carried out by the World Resource Institute (WRI). This “correction” of the WRI’s work is in no way intended as a criticism of them as a think-tank: I’m a big fan of the way they try to communicate key ideas through visualisations and figures. However, on reflection of its Sustainable Diets: What You Need to Know in 12 Charts article (based largely on its new paper Shifting Diets for a Sustainable Food Future), I couldn’t help but feel it was getting the global food, and particularly protein, story really wrong.

In the figure below, I’ve copied over the WRI’s visualisation of our global protein consumption, as an average by region (the green bars represent plant-based protein; the red as animal-based protein). The thickness of the bars is representative of the size of the population in that region. Now, the WRI’s analysis and interpretation of this figure is pretty simple. I quote: “All regions already consume more protein than average dietary requirements—with highest consumption in wealthy regions.” At first glance that does indeed appear to be the case—we know that especially for regions towards the right of the diagram, the resource intensity of animal-based protein production means that for sustainability reasons we probably need to reduce our intake. That’s pretty simple.

Protein Picture 1 (2015, non-adjusted for digestibility)

But what about the regions towards the left of the figure? Are they really “consuming more protein than average dietary requirements”? To answer this fairly, there are three key considerations/corrections I think we need to address.

Firstly, consider that the bars in the diagram represent the average protein intake per person by region. This means that some people will be consuming more, and some less than the represented average. How many are above and below this number and by how much? That’s a challenging question to answer, and largely depends on the regional inequalities in diets. But let’s keep it simple and say we have a normal distribution—all this means is that the distribution is symmetric, with half of a population consuming more than the average, and half less than the average. Protein Normal Distribution

If this were the case, it would mean that half of India—which has an average teetering on the recommended average line—would be protein malnourished. Asia and Sub-Saharan Africa would similarly have large portions of their populations in protein malnourishment. Let’s not underestimate what that means: we’ve suddenly moved from all regions over-consuming protein to several billion not consuming enough.

This is a key drawback of relying too heavily on average values. Averages can be great for trying to condense broad and often complex issues into simple messages (I utilise them a lot for this reason)—but if not used carefully, they can disregard large, and crucial, parts of the story. Averages work well when the distribution around them is small but unfortunately we live in a largely unequal world. Relying too heavily on them therefore runs the risk of over-simplifying the narrative.

But wait- it gets worse. The figure above considers only average bulk protein intake. It takes no account for protein quality or the human ability to digest it. “Protein” comprises a range of different building blocks—amino acids—and for adequate human nutrition, we need an adequate mixture of all of these. To take account of this, the World Health Organisation (WHO) and UN Food and Agricultural Organisation (FAO) developed a “Protein digestibility-corrected amino acid score” (PDCAAS) which attempts to correct for protein quality and truly evaluate the amount that can be digested for human nutrition. Unfortunately from a sustainability perspective, animal-based protein tends to have a much higher score than plant-based sources.

In the figure below I’ve attempted to show what happens to our previous representation when we correct for this digestibility factor¹. It’s further bad news for those at the left-hand side of our figure—those on predominantly vegetarian diets—here, even the average population intake falls well below the recommended requirement. In India, for example, we might conclude that the majority of the country are protein-malnourished. The same applies to Asia and Sub-Saharan Africa.

Protein Picture 2 (2015, corrected for digestibility).jpg

It gets worse still. The third correction we have to consider is the effect of population growth over the next few decades. By 2050, the UN predict that our global population will grow to approximately 9.5-10 billion. Of course, more people means more food and more protein. Where is most of this growth projected to occur? You guessed it: India, Asia and Sub-Saharan Africa—the three regions already in severe protein malnourishment. I’ve crunched the numbers and drawn the end result below²; it tells a pretty startling story. The average intake in India and Sub-Saharan Africa fall below half of the recommended intake [remember: this means that around half of the population could be even lower than the bar drawn]. More than half of the global population would already be, or be in severe risk of falling into, protein-malnourishment.

Protein Picture 3 (2050, corrected for digestibility).jpg

Through three quick analyses, we’ve suddenly moved far from the WRI’s message that all regions are over-consuming protein. But this is sadly the narrative that is being told over and over. The sustainability story of the right-hand side of the figure—that developed regions are consuming too much resource-intensive animal-based protein—is always the key focus. Don’t get me wrong: it’s a vitally important one. But let’s return to the basic definition of sustainability for a second: “meet the needs of the current generation without compromising the ability of future generations to meet their own”. The environmental community tends to place key emphasis on the latter half, often to the neglect of the former. When it comes to protein we’re not meeting the needs of the current generation. Several billion are protein-malnourished, and sadly their story is being completely missed from the global food narrative.

Does the world have a protein problem? Yes: a crucially important yet overlooked one. So through my PhD, I aim to address and converge both ends of the spectrum. The lower end deserves as much, if not more, attention than the upper one. To do so, we need to start to telling the full protein story.


¹To correct for digestibility, I’ve applied an average PDCAAS score of 0.65 for plant-based protein, and 1.0 for animal-based protein in line with FAO guideline figures.

²Note in this case that I’ve assumed global food production remains constant—admittedly this will not be the case. How agricultural efficiency, productivity and distribution will or could change in the coming decades is a topic too large to cover here.

Remembering David MacKay and his Unique Approach

Everyone has a story to tell about how they got to where they are today. Career paths can be driven by money, others by circumstance, many by passion, and for some, just pure coincidence. The biggest driver in my life has been people. The choice to venture into the world of sustainability appears to have stemmed from passion—who knows where this originates from. But importantly, my way of thinking towards sustainability and the approach I take to my work has been largely influenced by a few individuals. It has only just occurred to me that all three share the same name—one of these being David MacKay (Chief Scientific Adviser to the UK Department of Energy and Climate Change (DECC), and author of Sustainable Energy: Without the Hot Air).

It was with great sadness that I heard David lost his year-long battle with cancer, aged only 48. I felt it necessary to dedicate at least one blog post to him in the hope that his work can reach at least one other person. A person’s ideas, thoughts, teachings are not lost with their body, after all, and that at least is a comforting thought.

David MacKay.jpg

Anyone that has worked with me knows that I like working with numbers. Especially big numbers. In essence, I like to look at ‘big picture’ sustainability challenges. This didn’t come without its challenges: when I proposed my BSc dissertation idea I was told it was large enough for an MSc project; my MSc dissertation was more like a PhD proposal; and as I begin my PhD at the end of this year, I’m sure I’ll have some recommendations to “narrow it down”. But I probably won’t, because David MacKay taught me that the greatest value can often be added by stepping back and seeing the bigger picture.

For those who are unfamiliar with David’s work, he wrote the [I originally wrote “one of” but I’ve yet to read another on the same level] greatest and most influential book I’ve read on energy: Sustainable Energy—Without the Hot Air. When this was first released, my dad and I bought the paper copy, but David also generously published it online for free (investing £10,000 of his own money in doing so). I encourage anyone and everyone to take a look. However, if you’re looking for a more digestible form of his work, he also condensed it into a TED talk which you can watch here.

Sustainable Energy Without the Hot Air.gif

David’s approach in the book seems daunting to many; its pages are filled with numbers, equations and calculations. He was an engineer, after all, and his book is an obvious reflection of that. However, somewhat counterintuitively, what made this book so remarkable was its ability to make an issue (sustainable energy) which we nearly always treat as overly complex, and simplify it down to its most important considerations. Using the UK as his example, he asks two fundamental questions: “how much energy do we need?” and “if we maximise our energy production from sustainable resources, can we meet this demand?”.

His approach to these questions is what I think remains key to his legacy. He answered them through ‘big picture’ back-of-the-envelope calculations. Too often, especially in scientific disciplines, we let ourselves be held back by a lack of data, or data that ‘isn’t quite precise enough’. We convince ourselves that we need figures that are dead-on. David has shown that this simply isn’t true—in fact, probably quite the opposite: in order to look at large-scale complex issues we need crude number-crunching and back-of-the-envelope calculations. The moment you try to make it more precise than this, you lose the ability to simplify, the value in being able to identify and extract the key take-homes.

I read David’s book when I was 16/17 and in my first year as a university undergraduate. It was around the same period that I read Mike Berners-Lee’s “How Bad Are Bananas: The Carbon Footprint of Everything”. Both Mike and David tackled slightly different issues, but their approach is largely the same—neither shy from crunching rough (note that rough does not mean uninformed or poorly researched) numbers for fear of getting them wrong. That summer I did my own analysis of UK agriculture and land use ‘David MacKay style’. He has influenced my approach to every project, dissertation and piece of work I’ve done (including the PhD on global protein demand/supply I’m about to undertake). His book was equally inspiring to my dad, who has coined and developed a new integrated process for the production of Food, Feed and Fuel [you can find out more, here]—a development that would have been near-impossible to uncover without looking at the agricultural/food system with a ‘big picture’ lens.

The point is therefore that David MacKay should not only be celebrated for his contribution to UK energy. He has undoubtedly added so much value to this challenge, but he has done so much more. He should be remembered for his way of thinking, and the application/teaching of an approach that extends well beyond energy. I’ve applied it to agriculture and food. You could equally apply it to the evaluation of any resource. In fact, I’d argue that this transcends the field of sustainability too—you can literally apply it to any complex issue. In doing so, we can see these challenges through a clearer, simplified lens—a vital step if we’re to develop effective solutions.

So although we’ve lost one of our most intelligent thinkers, his way of thinking does not die with him. It lives on in everyone who applies it in their own work. And I suspect, based on his passion for teaching and learning (in all areas of his work, including his free books), that this would signify a life well-lived.

Many thanks to David MacKay: one of the best.

What Do You Mean “We Don’t Have a Paris Agreement”?

It’s been around two months since more than 190 countries signed on to the COP21 climate agreement in Paris. Except, technically they didn’t. As we battle out in fierce debates of whether the Paris agreement was a failure or flop, it’s sometimes easy to forget that nobody has actually signed on to anything yet.

In Paris we achieved the “adoption” of the international agreement—this is the process by which we establish the content, detail and form of what the agreement will entail. In other words, we decided what we plan to sign on to. The process whereby countries can actually sign (more technically termed “ratify”) doesn’t begin until April this year. The United Nations meet in New York on April 22nd where Heads of State can officially sign on to the agreement; nations are given a year’s deadline (until April 2017) to do so. Even then, signing doesn’t necessarily mean a country is included in the agreement—they then need to pursue their own domestic review and approval process, and report back to say that all domestic processes have been cleared*.

For the Paris agreement to officially come into action (i.e. become live), countries agreed on an “entry into force” mandate that 55 parties covering 55% of global greenhouse gas (GHG) emissions would have to join. If this requirement wasn’t met, the entire Paris deal would fall through and would cease to exist. I mentioned it in a previous blog post while the “entry into force” mandates were still being negotiated: 55% global emissions coverage is far too low. You can’t tackle the issue working with barely half of the world’s emissions. Plus, those signed on within that 55% would surely drop out pretty rapidly when they realised their efforts were being dwarfed by their counterparts.

55% Paris


So, given the fact that no one has signed the agreement yet, why have so many been celebrating like the deal is sealed? In short: it pretty much has been. I tend to err on the side of caution, however, this is one situation where I’m nearly 100% certain that most (if not all) of the parties in Paris will eventually sign the agreement. For most nations, the international backlash for choosing not to, would be too large. That’s one additional reason I’m pleased the reception to the details of the agreement has been so positive (there has been plenty of criticism too, but the majority has been on the mid-ground to optimistic side of the spectrum). If the reaction had been overwhelmingly negative, we’d be offering nations a prime opportunity to back out: “the consensus says that it’s doomed to fail anyway, so what’s the point of signing?”.

Having all nations sign might be a push too far, however, the 55 parties covering 55% of global emissions should be easily met. That’s why the following figures (see below) posted by the World Resources Institute (WRI) are largely speculative—I’d like to think we won’t have to calculate how far we are from 55% coverage. The figures are, nonetheless, another very interesting highlight of how much of our global emissions are dominated by a select few parties.

Some of the key stand-outs include:

  • You can’t have an agreement if neither of the biggest three parties (China, the US and EU) sign. It has always been apparent that realistically you can’t begin to tackle climate change without these parties, however, even the UN framework provides this mandate;
  • The 55 parties rule is an interesting one, and understandably intended by the UN to make the agreement truly global. See the top left pie chart, for example—even though China, the US and EU nearly meet the 55% coverage on their own, they’d still need another 52 parties to join (despite their collective emissions only adding about 10%);
  • The top-right pie chart is unrealistic: the EU is still mourning the loss of its neighbours in Kyoto, and has been one of the few parties trying to push for more ambitious targets. If any party was to drop out, it wouldn’t be them;
  • If China and the US both refused to sign the agreement (a scenario that would have seemed realistic, or even likely, in the past), nearly all other nations would have to sign to surpass the 55% threshold (as shown in the bottom pie chart);
  • The 55% requirement is based on current GHG emissions and takes no account of projected emissions growth. This underplays the influence of large growing nations (it was India in particular who brought my attention to it). Granted that basing figures on projected growth would be challenging and divisive to do, however, one of the key failures of the Kyoto Protocol was a failure to properly address the rapid emissions growth of large nations such as China and India, which eventually surpassed most developed nations.

55% Scenarios.png


As I mentioned, speculation about these figures are largely redundant since I expect the mandates will be easily met within the next year. Still, it’s still a revealing exercise to study the different scenario options (and how the fate of the agreement falls largely in the hands of a few key parties). Keeping a detailed eye on how the nitty-gritty of the UN and legal processes operate and evolve has been a steep learning curve. I doubt there will be any substitute for keeping up-to-date with these progressions in real-time—it develops an understanding of how international governance structures operate in a way that I simply couldn’t (and didn’t) gain from reading about past agreements such as Kyoto. The small, but crucial, aspects of the process were lost on me.


*This requirement made – what seemed like tedious bickering over non-essential fine-print – the legal wording of the specifics of the agreement extremely important (and led to the awkward final moments when the US raised the “should-shall” controversy). These minor fine-print details play a large influence in the domestic review process, and in case of the US would determine whether it had to be approved by Congress (a potentially make-or-break scenario).


Delhi’s Odd-Even Rule Is At Odds With What Needs To Be Done [Part 2]

[I  decided to provide an analysis of Delhi’s Odd-Even Rule in two parts for easier digestion: you can find some background on Delhi’s pollution issue, the rationale of the road rationing scheme and whether it’s working in Part 1 here]

The introduction of Delhi’s Odd-Even Vehicle Rule is unlikely to have the level of impact that many are expecting. But those who had studied the numbers had probably predicted that already.

Let’s briefly put the odd-even restrictions on vehicles into context. There have been quite a number of misleading reports over the last week (some from highly-respected sources) that Delhi will halve the number of vehicles on its roads. That’s unfortunately not true. First of all, the odd-even rule only applies to private four-wheel cars. Two-wheelers, three-wheelers, and trucks are not included (neither are buses but to ban them would be pretty counter-intuitive!). However, even if we said that it would halve the number of private cars, we’d still be wrong. There are a number of additional exemptions to the rule which limit this restriction further. The following are exempt:

  • Commercial vehicles (i.e. taxis-esque services)
  • Women drivers (solo, in a female-only car, or with children under the age of 12)
  • Private vehicles running on CNG (a cleaner type of fuel), as well as electric and hybrid cars
  • VIP escort vehicles (Presidents, Prime Minister, Union Ministers, Chief Ministers, judges, embassy vehicles)
  • Emergency vehicles (thankfully!)
  • People on their way to hospital for medical emergencies will be exempt on a “trust basis.”

In other words, the rule applies to non-VIP males driving a private petrol or diesel car. In which case, it’s slightly misleading to claim it’s “halving Delhi’s vehicles”.

Anyway, if this proportion of drivers comprise a large contribution to Delhi’s air pollution then the restrictions could still be effective. How do the number stack up? I had a hunt around to try to find some data on how Delhi’s pollution breaks down by source (shown below)*. As you can see, transport contributes 22-23% to the city’s PM2.5 concentration. [I should note that the contribution of different sources varies between seasons: in summer, vehicles only contribute roughly 10% to emissions—but since pollution levels are highest in the winter, I’ve used the 22% winter figures]. While we often assume that the main culprit of polluted cities is road traffic, sources such as waste-burning, diesel generators (especially in developing nations), industry, dust and domestic activities are surprisingly large.


Even if the odd-even rule did manage to halve the number of road transport vehicles (and correspondingly reduce their emissions by half), pollution levels would only be reduced by 11% (admittedly this is a decent chunk, but probably difficult to see clearly in amongst noisy measurements). But when we breakdown transport emissions further by vehicle (see below), we see that 4-wheel cars only contribute 4% to total emissions. In this case, even all private cars were included (i.e. no exemptions), we’d only be cutting emissions by a few percent at the most.


Targeting this small slice  is not only going to be deficient in scale, but improvements are likely to be largely outstripped in the long-term. A team of 6000-10,000 volunteers have been drafted in over the trial period to monitor implementation, and driver compliance has been impressive so far. However, such levels of monitoring are probably unsustainable and it’s likely that compliance will fall when this gets more lax. Some drivers could probably find ways of bypassing the rule by registration of different number plates. It’s also important to consider the staggering rate at which vehicles are being added to Delhi’s roads—approximately 1400 per day. From my calculations, if that rate were to stay the same, Delhi would have added around 2.5 million more within five years.

That raises a further concern: will this rate of increase stay the same? True, the restriction might discourage people from purchasing a vehicle, but it could have the opposite effect. For those with money, what’s one of the easiest ways to beat the scheme? Buy a second car with the opposite number plate (and probably an older, dirtier one if it’s your second). Of course, being able to afford one car isn’t economically feasible for many Delhiites, but with a rapidly growing middle class there is the potential to drive many towards buying a second. This has proven to be true in cities such as Beijing, Mexico City and Bogota.

The odd-even rule is a scheme focused on short-term rapid reduction in pollution. Beijing implemented it in the run-up to the 2008 Olympics and at the time it was pretty successful; I still didn’t envy the marathon runners, but they did experience a significant dip in emission levels. Several years down the line and Beijing’s pollution levels are nothing to envy.  However, at the time China also tackled the other key slices of the pie: it halted more than 100 factories and 56 power plants (mainly coal-fired) for the duration of the games. It also invested billions in its public transport (especially its metro and bus systems) to cope with the displacement in private travel.

This is exactly why Delhi needs to do the same, but with a long-term infrastructure focus. In terms of transport, the city needs a major focus on the improvement of its public transportation systems; it needs to make it favourable and attractive for people to choose public over private transport. That’s not going to happen if these options remain unreliable, overcrowded and unsafe. That’s not going to be an easy or cheap task, but it’s one the city needs to face, especially in light of its rapid economic and urbanisation growth rates. It’s also clear that focusing on transport won’t be enough to clean up Delhi’s air. Focusing on a single 22% slice is insufficient with pollution levels 16-20 times the recommended safe limit.

Despite my criticism of the trial, there are some positives to take from it. It has, if nothing else, drawn significant attention both nationally and internationally to the scale of the city’s pollution issues. There are clear signals that this is an issue that desperately needs to be addressed; the overwhelming response from Delhi citizens is another signal that the public pressure for change is strong. The reduction in traffic congestion has been another significant positive—many have noted the increase in productivity that reduced travel time could help.

It’s a start nonetheless, but falls well short of what’s needed. We don’t need to look at air quality measurements to see this—we could have predicted it from some background numbers. Ultimately, if you only tackle a little, you’re only going to achieve a little.


*Although there are small variations in quoted numbers from different sources, I’ve taken the most recent (2014) study data from the Central Pollution Control Board; CPCB (which has been widely cited) which I’d expect to be most legitimate. I haven’t seen any figures which vary hugely from these, so I’m going to assume they’re pretty close (or close enough to use for back-of-the-envelope context).