Why the US must Lead at Reducing Carbon Emissions

Sir David Attenborough, British naturalist and broadcaster, recently issued an urgent call to action on climate change at the World Economic Forum in Davos, Switzerland:

The only conditions modern humans have ever known are changing and changing fast. It is tempting and understandable to ignore the evidence and carry on as usual or to be filled with doom and gloom…. We need to move beyond guilt or blame and get on with practical tasks in hand.

In response to his call to action, we tried to determine which nations are leading to reduce their CO2 emissions. We’ve searched out facts on trends for CO2 emissions of advanced/developed countries. Here they are, along with some analysis. We will focus on:

  • Which nation has been most effective at reducing CO2 emissions at the highest rates recently? 
  • Which nation should be leading this effort?
  • Why the leading emitter must reduce emissions at a rate never done before?
  • A few changes that must happen for us to achieve our climate change goals.

Who has been most effective at reducing CO2 emissions at the highest rates recently?

Table 1 shows countries listed as ‘advanced economies’ by the International Monetary Fund, along with their annual average rate of CO2 emissions during 2010-2017 [a] [b].

It is important to consider trends in annual GDP growth rate when considering average emissions rates because CO2 emissions are linked with GDP growth for most countries. For Italy and Spain, GDP growth remained negative until 2014 according to the data here. For Denmark and UK, GDP growth remained consistently positive since 2010. Thus, we can consider Denmark and UK to be effective at reducing their CO2 emissions.

Who must lead? 

Since climate change is driven by cumulative CO2 emissions in the atmosphere, it is important to look at the countries in Table 1 from the perspective of how much each country contributes to global emissions.

Table 2 lists countries by their share in global CO2 emissions. We’re only considering countries with approximately 1% or more share of global CO2 emissions in 2017. You’ll see that the US leads all other advanced nations by a large margin; see the cell in red.

Note that the US has also the largest population. Maybe the largest population is why the US is the top CO2 emitter?

This is where a country’s CO2 emissions per capita help to see the whole picture better, since it normalizes variations in emissions due to population differences [c].

We see in Figure 1 that the US has the second highest per capita CO2 emissions rate.

Having the largest population and the 2nd highest per capita emissions among advanced countries makes it a priority for the US to reduce CO2 emissions[d].

But at what rate do we need to be reducing our emissions? Would it be enough if the US was as effective as Denmark & the UK at reducing emissions?

The race is on! The US must reduce emissions faster than any nation

The UK has a similar standard of living as the US. What if we aimed for their per capita emissions, reducing emissions at their rate (2.9% annually)? How long would that take? Figure 2 shows that it would take us 33 years, by 2050.

What if we sped up to Denmark’s emissions reduction rate (3.9% annually)? It looks like it would take us 24 years, per Figure 2, assuming of course that we had started in 2017.

the US has got to do better than matching UK’s per capita CO2 emissions levels. We need to aim for net zero per capita emissions before mid-21st century.

Australia and Canada have increasing CO2 emissions trends (0.1% and 0.8% annually) on average and have among the highest per capita emissions (16.6 and 15.3 metric tons). Reducing per capita emissions has to be a focus for them as well.  

Exactly how fast?

If we are to take the recommendation of the October 2018 report from the Intergovernmental Panel for Climate Change (IPCC) seriously, the US has got to do better than matching UK’s per capita CO2 emissions levels. We need to aim for net zero per capita emissions before mid-21st century. This statement is guided by one of the main recommendations from the October 2018 IPCC ‘Summary for Policymakers’ report.

In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030, reaching net zero around 2050.

We are going to repeat this. To avoid bringing the average global temperatures above 1.5C, worldwide CO2 emissions must become net zero by the year 2050, and each country is responsible.

If our goal isn’t just to match the UK’s annual per capita emissions of 6 metric tons, but to get to zero metric tons by 2050, how fast will we need to go? Looking at Figure 2, 8% annually will get us to 1 metric ton per capita. This is a rate seen never before.

Must we change course? Yes. Can we change course? Yes. Will we change course? Only time will tell. We got a man on the moon, this is certainly a race worth getting into! 

What’ll it take to get to net-zero emissions?

In our view, the following steps must be taken to move towards reaching net-zero emissions because a delay will make limiting global temperatures to 1.5C even harder. These steps are derived from professional experience in the renewable energy industry and the works of David Roberts and Hal Harvey.  

Decarbonization – It will be necessary to capture the remaining CO2 from the atmosphere. Low cost measures, such as tree plantation at scale, can go a long way in capturing CO2.   

Grid Flexibility – Until we have cheap, long term energy storage on scale, the grid has to be made flexible to accommodate increasing wind and solar capacity. At the same time, there have to be efforts at reducing our dependence on natural gas and find ways to maintain the grid flexibility we currently have. This is where energy storage and demand side management come in. Electric utility companies have a huge role here.

Investment in Energy Storage R&D – Starting from cyanobacteria billions of years ago to plants today, nature figured out how to convert and store sunlight for its needs via photosynthesis. It’s now in our interest to increase investment in research & development of energy storage technologies to store solar and wind energy beyond a few hours.  

Electrification of (almost) all Applications – Unless we have a net-zero carbon fuel available on a large scale, applications such as space heating, shipping and eventually aviation will have to move away from using fossil fuels.

Effective Energy Policy & Market Forces – The right set of policies, which are consistently monitored and updated, such as building codes or vehicle efficiency standards, can go a long way in reducing CO2 emissions. Also, when there is a market for the services offered by technologies, such as grid connected lithium-ion batteries, it helps investors earn a favorable rate of return, which leads to deployment of the technology at scale and further helps in reducing costs.

To know more about how much progress is being made at limiting warming to 1.5C, see the Climate Action Tracker. Also, the check out the Climate Change Performance Index 2019 to see which countries are leading the efforts at Greenhouse gas emissions, Renewable Energy, Energy Use and Climate Policy. You can also check out this brief article from Bill Gates, where he explains what it will take to stop climate change.

A collaborative post by Aditya Saxena & Meenal Raval of 350 Philly


  • [a] Data on annual CO2 emissions by use of fossil fuels from The United Nations Framework Convention on Climate Change (UNFCCC) (for years 2000 to 2016) and BP Statistical Review of World Energy (for Year 2017). The data considers CO2 emissions from combustion of fossil fuels only and does not include removal of CO2 from the atmosphere into any kind of ‘sinks’, also categorized as ‘land use, land-use change and forestry’ or LULUCF.
  • [b] We calculated average annual rate of emissions for two time periods: 2000-2017 and 2010-2017, deciding to select the 2010-2017 to minimize the effects of the economic recession which lasted from December 2007 to June 2009 in the US and affected most advanced nations in North America and Europe. Even the CO2 emissions data confirmed this fact. All countries in Table 1 had negative CO2 emissions rates for years 2008 and 2009. And except for Cyprus, Ireland, Greece, Portugal & Spain, all countries had positive emission rates in 2010. If you’re interested in emission rates for the 2000-2017 period, see this document.
  • [c] Per capita emissions can be calculated simply by taking the total CO2 emissions of a country/state (generally in metric tons) and dividing it by its total population.
  • [d] It can be claimed that US has had the largest reduction in actual metric tons of CO2 than let’s say, UK, as claimed here,here and here. Using figures in actual metric tons of CO2 avoided and claiming that the country is ‘leading at reducing emissions’ or ‘effective at combating global warming’ is, in our view, misleading. In Table 1, we noted that the average rate of reduction for US is -0.5% and for UK is -2.9% for 2010-2017 period. Even a small percent reduction in the total CO2 emissions of US (5087.7 million metric tons) can be larger than a higher percentage reduction in much smaller total CO2 emissions of UK (398.2 million metric tons), simply because US emissions are so much larger than that of UK (12.8 times). This is why, in our view, the average rate of annual emissions is a better indicator of which country is leading at reducing CO2 emissions.

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