Who is most to blame for climate change? Regardless of the answer, global cooperation is critical

Climate change is one of the biggest existential threats to humanity, but in the ongoing struggle to fight it, a debate rages on over which countries are most responsible for emitting the greenhouse gases accelerating the crisis. China currently emits more CO2 than the U.S., but both countries are the world's top producers of the heat-trapping compound. Yet doesn't just matter who currently emits the most, but also how long they've been doing it and what those countries are doing to curb emissions.

The stakes could not be higher. Humans are experiencing the hottest months in recorded human history, with scientists warning that humanity is living on "borrowed time." As climate change worsens people can expect frequent and intensified tropical storms, wildfires, droughts and heatwaves, as well as rising sea levels and resource scarcity. This has put a spotlight on the issue, as well as on questions of how to fix the problem. Salon spoke to several climatologists about America's role in both causing and solving climate change, and all of them agreed on two things: First, America is the world's largest legacy climate polluter — that is, they have put more total carbon pollution into the atmosphere than any other nation; and second, a heavy burden therefore falls on America to take responsibility.

"In 2023, global temperatures came close to 1.5º C above pre-industrial levels – and the US is by far the biggest contributor to that," said Dr Simon Evans, Senior Policy Editor at the policy website Carbon Brief, which among other things keeps track of greenhouse gas emissions. Evans said that their analysis shows that more than one-fifth of all the warming currently being experienced on Earth was caused by America's cumulative greenhouse gas emissions. Even though China has a much larger population than the United States (1.4 billion versus 333 million), their total role in causing global warming is only around half of America's contribution. Furthermore, China is the leader of transitioning to renewable energy.

It is "relatively easy" to estimate any country's contribution to climate change — or, for that matter, any industrial sector's contribution, Dr. Gavin A. Schmidt, a climatologist and Director of the NASA Goddard Institute for Space Studies, told Salon. He referred interested parties to a website that helps ordinary citizens acquire that information for themselves. When they do so, it is important for them to understand the science behind how climate change is happening.

"The dominant driver of current climate change is CO2 emissions, and they have a property that means (roughly speaking) that the impact on climate is related to the accumulated emissions of CO2," said Schmidt. "This is different to the impact from air pollution or methane whose effects are really just related to current emissions. So that means you can relatively easily estimate any country’s (or any sector’s) contribution to current climate change by just looking at their cumulative CO2 emissions."

By doing that, it's clear that the United States has had the largest impact, followed by the European Union, China and the United Kingdom.

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According to some climatologists, America's disproportionate role in causing climate change puts a burden on the United States to take the lead in addressing the issue.

"This means that it is absolutely essential that the U.S. take a leadership role in global climate action," said Dr. Michael E. Mann, a climatologist at the University of Pennsylvania. He said this should include "reducing carbon emissions by 60% over the next decade. Without American leadership, it’s easy for other countries to come up with excuses and do less, and even back-pedal."

Mann added, "That’s what we saw during the Trump presidency, when the U.S. signaled to the rest of the world it was no longer serious about climate action."

Dr. Peter Kalmus, a NASA climate scientist who emphasized his opinions are his own, criticized the United States for not doing more to tackle climate change.

"The U.S. needs to get its own climate ducks in a row before the other nations of the world will listen to it on climate policy," said Kalmus. "The U.S. has the wealth and technology to be a powerful global leader on climate action, but instead continues to double down on fossil fuels, which is so incredibly stupid. We've squandered the chance to do good in the world and in doing good in the world to ensure a strong post-carbon economy for ourselves. It's just so stupid. "

Salon also spoke with Dr. James Hansen, a climatologist at Columbia University whose 1988 Senate testimony was a landmark event in the history of spreading public knowledge about global warming. Hansen said that "the fossil fuel industry decided to deny climate change rather than begin to invest in carbon-free energies." Because they discovered "it was easier to buy off politicians" than invest in green technology, oil companies have stymied efforts to spread public awareness about climate change and thereby cultivate the collective will to implement solutions. According to Hansen's recent paper in the journal Oxford Open Climate Change, feasible solutions do exist.

"That means a simple honest rising price on carbon, implemented in a way that the public will accept, i.e., with the funds collected from the fossil fuel industry distributed to the public," Hansen said. "Additional details include the need for 'clean energy portfolio standards' not 'renewables-only portfolio standards.'"

Hansen said that although President Joe Biden has attempted to address this issue — and he, unlike Trump, recognizes the scientific reality of climate change — his policies fall far short of what is needed. Hansen described the Inflation Reduction Act, which included environmental measures, as a bill that "produces inflation by borrowing huge sums from our children and grandchildren, but which has only [a] slight effect on reducing global emissions."

Now that America has failed to take the lead globally, Hansen argues that they may have permanently forfeited their world leadership on this front.

"Given that we failed to help get effective global policies, China is now the greatest source of present and future emissions," said Hansen. He said that "we should give priority to working with China. Instead we are intent on painting them as our enemy, an approach that tends to be self-fulfilling. The hope now is that Europe will be smart enough to not follow that lead."

The bottom line is that pointing fingers at who is the "worst" polluter is probably not a very productive use of time and energy, especially as the clock is ticking to avoid the worst effects of our changing climate. International cooperation will be key — after all, global heating is a global problem.

"Speaking personally, I think that obliges the U.S. to be a leader in the energy transition — i.e. you broke it, you fix it," Schmidt said. "But I don’t think it means that it’s all on the U.S. Rather, all the big emitters need to get their emissions down."