The Global Climate Summit has begun in Glasgow, Scotland, and it is imperative that the world’s leaders make binding commitments to significantly reduce greenhouse gas emissions. There is some reason for optimism. The average global temperature by 2100 was projected to increase 6.5-7.5 degrees Fahrenheit over preindustrial temperatures, but thanks to efforts initiated from the Paris Climate Agreement, the projected increase is now 4.9-5.6 degrees. With global temperature already 2 degrees above preindustrial times, substantial efforts are needed to hold the long-term temperature increase to 2.7 degrees, the most realistic minimum increase.
Global warming is caused by accumulation of greenhouse gases including carbon dioxide. Historically, the U.S. has contributed the most carbon dioxide to our atmosphere, but by 2018 China was emitting 10.3 billion metric tons of carbon dioxide, followed by the U.S. (5.0) and India (2.4). On a per capita basis, the U.S. leads by a long shot (15.1 metric tons per person) compared to China (7.4) and India (1.8). For the U.S., the largest contributing activities are transportation (35 percent) and power generation (31 percent). Carbon dioxide emissions today contribute to global warming for thousands of years.
Methane emitted today only lasts about 10 years, but its warming potential is 28-36 times that of carbon dioxide. This is because methane absorbs more energy (heat) than carbon dioxide, and methane is a precursor to ozone, which is another global warming contributor. In carbon dioxide “equivalents,” China leads with 1.2 billion metric tons followed by India (.7) and the U.S. (.6). In the U.S., animal agriculture and manure management account for 36 percent of methane production while the natural gas and petroleum systems account for 30 percent of emissions.
Nitrous oxide emitted today hangs around for about 100 years and it is a much more potent greenhouse gas, equivalent to 265-298 times that of carbon dioxide. The leading emitters are China with the carbon dioxide equivalent of .54 billion metric tons, followed by India and the U.S. (both .25). In the U.S., the primary sources of nitrous oxide are agriculture and industrial activities. Fluorinated gases also contribute to global warming given that they can be equivalent to 1,000 times more potent than carbon dioxide, although the quantities involved are much lower than other gases of concern.
Based on these data (which come from the EPA and World Bank), we can conclude that the U.S. is one of the top three emitters of important global warming gases and, on a per capita basis, we are by far the largest contributor to this crisis. And while methane and nitrous oxide are important, carbon dioxide remains the dominant threat with the bulk of this coming from transportation and energy production.
In this respect, it is encouraging to see that the surviving parts of the Biden domestic policy bill are focused on transportation and energy. It isn’t finished yet, but disincentives for using fossil fuel to generate electricity are largely gone from the bill thanks to coal-loving West Virginia and their champion, Sen. Joe Manchin. That’s also thanks to the do-nothing Republicans who sit in the peanut gallery lobbing snarky comments at everything they see while contributing no meaningful ideas.
Nevertheless, the bill still includes money for grants and loans that can be used by industry (including agriculture) to shift to clean energy providers, tax credits and infrastructure investments to increase solar and power production, and tax credits designed to dramatically increase the number of electric cars on the road, plus refundable home improvement tax credits for renewable energy investments.
These investments coupled with a pending EPA rule designed to curb methane production and other state-level actions should put the U.S. on course to cut greenhouse gas emissions by 2030 to half of our emissions in 2005.
Failing to do so means a grim future for the world according to an Oct. 21 National Intelligence Estimate. Besides intensifying natural disasters and shifting weather patterns that will impact everyone, the world will experience massive displacement of people, and increasing uncertainty in global financial markets.
The social, economic, and ecological damage and uncertainty will hurt everyone, but of the 11 countries expected to fare the worst, three own nuclear weapons (North Korea, Pakistan, and India). We need to invest now to make a better world for the next generation.
Call (he/him) is a microbiologist and fatherof three. He first discovered the Palouse 38 years ago.