Scientists have worked out how the US could save as many as 300,000 lives by 2030, and get a tenfold return on its investments at the same time.
It’s simple. All the nation has to do is what it promised to do at the Paris climate conference last December − launch clean energy and transport policies, reduce greenhouse gas emissions by two-thirds or more, and pursue the international goal of keeping global warming to below 2°C.
Drew Shindell, professor of climate sciences at Duke University, North Carolina, and colleagues report in Nature Climate Change that the climate policies agreed by 195 nations at the latest UN summit on climate change deliver a winning scenario for the most powerful nation on Earth.
If the US pursued the switch to electric cars and renewable energy, hundreds of thousands of premature deaths could be prevented − not just by containing global warming and limiting the extent of climate change, but by the consequent reduction in soot, aerosols and ozone, all of which are pollutants with consequences for health.
And although such policies would cost considerable sums to implement, the money saved in the long run would exceed expenditure by between fivefold and tenfold. Even in the short term, benefits of up to $250 billion a year are likely to exceed implementation costs.
“Achieving the benefits, however, would require both larger and broader emissions reductions than those in current legislation or regulations,” the scientists warn
Calculations like these are never easy: researchers have to propose conditions that have yet to happen, and match them against benefits that for the same reason cannot be measured and, even after the event, could not in any case be confirmed.
But Professor Shindell and his colleagues have done it anyway. They looked at the notorious “business-as-usual” scenario, and then at US transportation emissions reductions calculated to avoid 0.03°C global warming by 2030, and 0.15°C in 2100. Then they considered energy emissions reductions aimed at avoiding 0.05°C warming in 2030, and 0.25°C in 2100.
The clean energy policies would prevent 175,000 premature deaths by 2030, with 22,000 fewer annually thereafter. Clean transport policies could prevent 120,000 premature deaths by the same year, and about 14,000 annually thereafter.
Calculations like these are based on a wide range of assumptions, and so are the potential rewards. Near-term national benefits could be anything from $140 billion a year to $1,050bn by 2030, but the Duke scientists settle on a likely figure of $250bn. Altogether, by 2030, the US would have saved $1,200bn under their proposals.
But if other countries do the same thing, the benefits would begin to multiply with the decades. Those benefits, the scientists say, would roughly quintuple, and could be 10 times larger than implementation costs.
“The US has pledged to markedly reduce emissions that cause warming, but has left many details to be determined later,” the scientists say − which is why they constructed their own emissions scenarios.
In their calculation of benefits, they do not factor in the wider costs of climate change, in a greater frequency of extreme events such as floods, hurricanes, drought or heatwaves. They also do not consider coastal damage from sea level rise, or the costs to agriculture of drought that might be saved by emissions reductions.
And, they concede, they put a value only on one big benefit from future clean energy and transport policies: the lives saved by cleaner air.
But effects on medical spending and worker productivity could add to the value. The consequent pollution reductions could, for instance, prevent 29,000 asthma attacks among children under 18 – attacks severe enough to require visits to a hospital emergency room – and could prevent up to 15 million lost working days a year among adults.
The proposals sound like a win-win offer. But the Duke scientists are aware of the problems. Their suggestions go twice as far as policies yet to be implemented in the US Clean Power Plan, and the costs of implementation would not be fairly spread.
They end on a note of realism: “Most benefits would accrue to society at large, whereas businesses that could face economic losses would not directly benefit from decreased emissions.
“These misaligned economic incentives between the welfare of individual companies and that of society at large create substantial implementation barriers.”