How to judge America’s climate-change responsibility
Historically, America has emitted the most greenhouse gases of any country in the world. But over the next 80 years, the U.S. may account for as little as 5% of such emissions.
Why it matters: Installing technologies to address climate change will, therefore, be most critical in places other than America where emissions’ growth is expected to be higher, according to physicist Varun Sivaram.
The intrigue: This concept, described to me by Sivaram, an expert at Columbia University, is counterintuitive given America’s wealth and historical responsibility for warming the planet. Sivaram, a former top executive at a large renewable energy company in India, calls this the 5% and 95% problems.
The big picture: Most debate and policy work in the U.S. focuses, not surprisingly, on how America can reduce its own emissions. President-elect Joe Biden has a 2050 goal for a U.S. economy that, on net, emits zero greenhouse gases. More and more companies and states are setting similar goals.
What they’re saying: That’s all directly tackling, in Sivaram’s words, the 5% problem — not the 95% of future cumulative emissions outside of the U.S.
- “Is it important to reduce our emissions to net zero and to meet 2050 targets? Yes,” Sivaram says. “But is it of equal importance to reducing the 95% problem? Probably not.”
By the numbers: Sivaram says the U.S. share of global carbon emissions, now at 15% and second to China, will likely decline over the rest of the century because our energy demand is relatively flat compared to rapidly growing demand in other parts of the world, especially Asia.
- He estimates that if U.S. emissions are cut by a third over the next 30 years and another half by 2100, then future U.S. cumulative emissions this century will be roughly 5% of the global total under a baseline scenario for global emissions.
- Sivaram gets this estimate by assuming a little more policy and innovation compared to business as usual but still far less ambition than Biden’s goal.
Where it stands: The U.S. should, of course, act on climate change, Sivaram says. He argues that its initiatives need to speed global transitions to cleaner energy, not just domestic progress. In other words, tackle the 95% problem and the 5% problem.
- The most important things the U.S. can do are innovate and effectively deploy a range of clean-energy technologies in affordable ways, he says.
- “From India’s perspective, for example, they're only going to decarbonize if it's affordable, and the U.S. can be most helpful by mobilizing financing or investing in demonstrating clean industrial technologies in India," Sivaram said. "They certainly won't just follow our example if the U.S. pursues an expensive clean energy transition."
Yes, but: Sivaram’s concept doesn’t deny that the U.S. bears much of the responsibility for climate change, a debate that’s increasing with Biden’s victory.
- More than 100 activist groups are pushing a campaign called the “U.S. Climate Fair Share.” The coalition sent a letter to the transition team last week calling on the president-elect to cut domestic emissions even more aggressively to make up for America’s historical contribution to warming the planet.
- “The crisis that we’re facing now is caused by the cumulation of emissions over time from the past to the present,” says Rachel Rose, director of climate research and policy at Corporate Accountability, one of the groups leading the effort.