Cutting carbon emissions could save 153 million lives, study finds
As many as 153 million deaths linked to air pollution worldwide this century could be prevented if governments speed up timetables for reducing fossil fuel emissions.
That is the claim of a new study which looked at the numbers of people in urban areas whose lives could be saved if temperature increases are limited to 1.5°C (2.7°F).
The study is the first to project these numbers on a city by city basis, in 154 of the world's largest urban areas.
In New York, Los Angeles, Moscow, Mexico City and Sao Paolo alone, between 320,000 and 120,000 premature deaths would be prevented in each city.
Researchers say the study shows why politicians and governments should act swiftly to bring down carbon emissions.
Scroll down for video
As many as 153 million lives worldwide could be saved this century if governments speed up their timetable for reducing fossil fuel emissions, new research suggests (stock image)
Researchers from Duke University ran computer simulations of future emissions of carbon dioxide and associated pollutants, such as ozone and particulate matter, under three different scenarios.
These scenarios simulated an overall increase in emissions resulting in warming of 2°C (3.6°F) by 2100, accelerated reductions of carbon emissions, and even further reductions limiting atmospheric warming to 1.5°C (2.7°F).
They matched this data with computer models, based on decades of public health data on air-pollution related deaths, to work out which areas would be the hardest hit by global warming.
They then calculated the human health impacts of pollution exposure under each scenario all over the world, focusing on major cities.
Under the third scenario, premature deaths would drop in cities on every inhabited continent, the study shows, with the biggest impact in Asia and Africa.
Thirteen Asian or African cities could each avoid more than one million premature deaths.
In Delhi as many as four million lives would be saved and around 80 additional cities could each avoid at least 100,000 deaths, researchers found.
The new projections underscore the grave shortcomings of taking the lowest-cost approach to emissions reductions, according to the researchers.
This permits emissions of pollutants to remain higher in the short-term in hopes they can be offset by negative emissions in the far distant future (stock image)
Under this approach, emissions of pollutants are allowed to remain higher in the short-term in hopes they can be offset by negative emissions in the far distant future.
Dr Drew Shindell, professor of Earth sciences at Duke, said: 'The lowest-cost approach only looks at how much it will cost to transform the energy sector.
'It ignores the human cost of more than 150 million lost lives, or the fact that slashing emissions in the near term will reduce long-term climate risk and avoid the need to rely on future carbon dioxide removal.
'That's a very risky strategy, like buying something on credit and assuming you'll someday have a big enough income to pay it all back.'
The landmark Paris climate agreement in 2015 called for capping global warming at 'well under' 2°C (3.6°F) compared to a pre-industrial benchmark, and pursuing efforts for a 1.5°C (2.7°F) ceiling.
WHAT WERE GLOBAL TEMPERATURES IN 2017? Earth’s global surface temperatures in 2017 ranked as the second warmest since 1880, according to an analysis by Nasa. Continuing the planet's long-term warming trend, globally averaged temperatures in 2017 were 0.90°C (1.62°F) warmer than the 1951 to 1980 average, according to scientists at Nasa’s Goddard Institute for Space Studies (GISS) in New York. That is second only to global temperatures in 2016. In a separate, independent analysis, scientists at the National Oceanic and Atmospheric Administration (NOAA) concluded that 2017 was the third-warmest year in their record. This map shows Earth’s average global temperature from 2013 to 2017, as compared to a baseline average from 1951 to 1980, according to an analysis by Nasa. Yellows, oranges, and reds show regions warmer than the baseline The minor difference in rankings is due to the different methods used by the two agencies to analyse global temperatures, although over the long-term the agencies’ records remain in strong agreement. Both analyses show that the five warmest years on record all have taken place since 2010. Because weather station locations and measurement practices change over time, there are uncertainties in the interpretation of specific year-to-year global mean temperature differences. Taking this into account, Nasa estimates that 2017’s global mean change is accurate to within 0.1°C, with a 95 per cent certainty level. 'Despite colder than average temperatures in any one part of the world, temperatures over the planet as a whole continue the rapid warming trend we’ve seen over the last 40 years,' said GISS director Gavin Schmidt.
However, the UN has projected that in a worst-case scenario the world could warm by as much as 6°C (10.8°F) by 2100.
'Since air pollution is something we understand very well and have extensive historical data on, we can say with relatively high certainty how many people will die in a given city under each scenario, Dr Shindell added.
'Hopefully, this information will help policymakers and the public grasp the benefits of accelerating carbon reductions in the near term, in a way that really hits home.'
The full findings of the study were published in the journal Nature Climate Change.