US, China and Russia the top CO2 polluters since 1850, analysis finds

CO2 lasts for centuries in the atmosphere and the more that is released, the more heat is trapped.
CO2 lasts for centuries in the atmosphere and the more that is released, the more heat is trapped.PHOTO: REUTERS

SINGAPORE - When it comes to international climate diplomacy, responsibility for all the carbon pollution in the atmosphere really matters.

The bigger the polluter, not just now but also historically, the greater the responsibility for the warming of the planet to date.

That is because there is a strong correlation between the total amount of carbon dioxide (CO2) released by human activity and the level of warming at the earth's surface, says Dr Simon Evans, deputy-editor of Carbon Brief, a specialist British-based website covering climate science and policy, and energy policy.

At the COP26 climate talks in Glasgow starting at the end of this month (October), historical responsibility will be a key focus for poorer, vulnerable nations which want justice for the severe climate impacts they suffer because of the emissions from big economies that have grown rich from burning fossil fuels.

In a recent analysis, Dr Evans looked at the nations historically responsible for most of the CO2 emissions that have accumulated in the atmosphere since 1850.

He looked at the emissions from fossil fuels and cement production and from land use change and forestry - mainly deforestation.

The results? The United States, China and Russia account for nearly 40 per cent of accumulated CO2 emissions from human activity. Brazil and Indonesia (ranked fourth and fifth) are responsible for another 8.6 per cent, largely because of decades of deforestation.

Germany comes next in the top 10 list, followed by India, Britain, Japan and Canada.

CO2 lasts for centuries in the atmosphere and the more that is released, the more heat is trapped - meaning CO2 emissions from hundreds of years ago continue to contribute to the heating of the planet.

That means the cumulative amount of CO2 emitted since the start of the industrial revolution is closely tied to the 1.2 deg C of warming that has already occurred.

Dr Evans looked at national totals based on territorial CO2 emissions, reflecting where the emissions have taken place. In addition, the analysis looked at the impact of consumption-based emissions accounting, to reflect trade in carbon-intensive goods and services.

Estimated historical emissions from land use change and forestry take into account sizeable CO2 production from deforestation for agriculture, mining and urban expansion over the decades.

By the end of this year, the US will have emitted more than 509 billion tonnes of CO2 since 1850, according to the analysis. This represents 20.3 per cent of the global total, the largest share, and is associated with about 0.2 deg C of warming to date.

In second place is China, with 11.4 per cent of cumulative CO2 emissions to date and around 0.1 deg C of warming. China has had high land-related emissions since 1850, but its coal-fired economic boom since 2000 is the main cause of its current position, Dr Evans said.

China's CO2 output has more than tripled since 2000, overtaking the US to become the world's largest emitter, responsible for about 28 per cent of mankind's annual CO2 emissions versus 15 per cent for the US.

In total, humans have pumped around 2,500 billion tonnes of CO2 into the atmosphere since 1850, leaving less than 500 billion tonnes of CO2 of remaining carbon budget to stay below 1.5 deg C of warming.

By the end of this year, the world will collectively have burned through 86 per cent of the carbon budget for a 50 per cent chance of staying below 1.5 deg C.

What this means is that at the present rate of annual CO2 emissions, the remaining carbon budget will be blown in about a decade, placing the world on a path towards far greater climate extremes.

A striking result of the analysis is the historical contribution from land use and forestry, which added 786 billion tonnes of CO2 from 1850 to 2021. That is nearly a third of the cumulative total. The remaining two-thirds come from fossil fuels and cement, with cement production alone accounting for about 7 per cent of humanity's CO2 emissions.

Aerial view of a deforested area close to Sinop, Mato Grosso State, Brazil, on Aug 7, 2020. PHOTO: AFP

Deforestation for development and agriculture has been a consistent part of economic growth for centuries for many nations.

Settlers and colonialist-run farms in Brazil and Indonesia cleared land to grow cash crops such as rubber, sugar and tobacco.

Deforestation accelerated rapidly in the last half of the 20th century to create cattle ranches, plantations for industrial-scale crops such as soya, palm and pulpwood and logging.

"We think this analysis shines an even stronger light on the need to consider land use and deforestation emissions and not only focus on fossil fuel emissions," Mr Leo Hickman, the director and editor of Carbon Brief, told The Straits Times.

Looking at the historical emissions data another way, based on cumulative emissions per population today, reveals a very different picture.

China, India, Brazil and Indonesia drop out of top 10. Instead, based on per-capita emissions, Canada comes out first, followed by the US, Estonia and Australia.

"While these countries (China, India, Brazil and Indonesia) have made large contributions to global cumulative emissions, they also have big populations, making their impact per person much smaller," said Dr Evans in his analysis.

"Indeed, those four countries account for 42 per cent of the world's population, but just 23 per cent of cumulative emissions from 1850-2021."

By contrast, the US, Russia, Germany, Britain, Japan and Canada account for 10 per cent of the world's population, but 39 per cent of cumulative emissions.