Hurricane hell and climate punishment
It’s hurricane season again, and as The Hill has reported, the U.S. National Oceanic and Atmospheric Administration (NOAA) warns that this year is expected to be worse than usual, for the seventh consecutive year. Climate change is making these storms — also called cyclones or typhoons in other parts of the world — more frequent and damaging. More than 90 percent of the extra heat from global warming is going into the oceans, and the warmer waters are putting more and more destructive energy into hurricanes. That’s simple physics. And it can be hell for low-lying islands and coastal areas.
But there are also some important subtleties, including the challenge presented when we reduce air pollution and thereby “unmask” existing warming. This happens, for example, when we close down a coal plant, which emits cooling sulfate pollutants as well as the carbon dioxide that heats the atmosphere.
These sulfates offset, and thus partially hide, the warming from the carbon dioxide, but they fall out in a matter of days to weeks, while the carbon dioxide stays in the atmosphere for centuries. In this way, air pollution is masking about a half a degree Celsius of global temperature rise that is already baked into the atmosphere according to the Intergovernmental Panel on Climate Change.
Over the last four decades, North America and Europe have succeeded in cutting particulate air pollution from energy use by an estimated half, and this has had a knock-on effect both on hurricanes and global warming, as a whole.
Air pollution, including the cooling sulfates, peaked in the 1980s over the North Atlantic, and as it has declined the number of hurricanes in the North Atlantic has increased in response to the resulting warming.
New research by NOAA published last month in the journal Science Advances concludes that this unmasking process has thus been a key ingredient in a 33 percent increase in the number of hurricanes in the tropical Atlantic Ocean over the last 40 years. And, it adds, it has also caused the jet stream to move northward, which also helps hurricanes to develop and grow stronger.
These conclusions are given even greater weight by studying what is happening in Asia, where precisely the opposite process has been taking place. There, the research concludes, a 40 percent increase in particle air pollution has contributed to a 14 percent decrease in tropical cyclones.
The NOAA study is the second major piece of research in the last few weeks to focus attention on the crucial importance of the particles — and of reducing their pollution — for climate change.
Last month, a study by scientists at Georgetown University, Texas A&M University and the Scripps Institution of Oceanography at UC San Diego, and UC Santa Barbara, and others — to which we also contributed — concluded that cooling particles had offset nearly half of the warming so far caused by fossil fuel burning and carbon dioxide from land use change and that therefore, as they were reduced, climate change would escalate.
Our study in the Proceedings of the National Academy of Sciences added that cutting fossil fuel emissions by decarbonizing the energy system and shifting to clean energy — governments’ dominant strategy for combatting global warming —would, if pursued in isolation, actually make things worse in the short term and would on its own not be able to prevent global temperatures exceeding 1.5 degrees Celsius above pre-industrial levels. That is the internationally accepted guardrail beyond which the world’s climate is expected to pass irreversible tipping points. Indeed, it would be unlikely to stop temperatures going past even a much more hazardous 2-degrees Celsius increase.
The only way to avoid catastrophe, our study concluded, is to simultaneously cut other non-carbon dioxide super climate pollutants at the same time as decarbonization is reducing carbon dioxide. This has planet-saving potential.
Reducing emissions of the short-lived super climate pollutants — methane, hydrofluorocarbon refrigerants, black carbon soot and ground-level ozone smog — as well as long-lived nitrous oxide would slash the rate of warming in half from 2030 to 2050 and give the world a fighting chance to stay below the critical 1.5-degree Celsius guardrail.
Cutting emissions of methane — which is 86 times more effective in heating the planet than carbon dioxide over 20 years — is especially urgent, and is both practicable and cost-effective; over half the required measures would quickly pay for themselves.
This, like the important linkage between decarbonization and unmasking, is now starting to get the attention it deserves. Last November, over 100 countries, representing half of the world’s emissions, launched the Global Methane Pledge at COP26 climate summit in Glasgow to reduce them by at least 30 percent this decade.
The White House, the EU and the other countries took an important step on Friday in implementing the pledge at President Biden’s Major Economies Forum meeting. They agreed an “energy pathway to catalyse methane emissions reductions in the oil and gas sector,” which contributes about one-quarter of all human-caused methane emissions, through flaring, venting and leaking the gas.
The pathway encourages all nations to capture the maximum potential of cost-effective methane mitigation in this sector and to eliminate routine flaring as soon as possible, and no later than 2030. Governments at the forum agreed to provide nearly $60 million in dedicated funding in support of the pathway and described efforts they were themselves making to reduce emissions.
The U.S. and EU also are discussing the need for countries providing gas to replace supplies sanctions from Russia to ensure that producing it involves as little leakage of methane as possible. Indeed, a new report by the International Energy Agency concludes that reducing methane emissions from oil and gas operations, including by flaring, could make a staggering extra 210 billion cubic metres of gas available to markets. Making such savings in countries that currently export gas to the EU, could reduce its imports from Russia by one-third.
The report also concluded that rapidly deploying all the technologies already available to reduce emissions from the oil and gas sector would avoid nearly 0.1 degrees Celsius of warming by 2050 — equivalent to eliminating the greenhouse gas emissions of all the world’s cars, trucks, buses and two-and three-wheelers.
The next step must be to agree to a methane agreement — inspired by the phenomenally successful Vienna Convention and Montreal Protocol, which have phased out substances that destroy the world’s protective ozone layer, while also avoiding warming that otherwise would have equalled what carbon dioxide is causing today.
Urgent measures must still be taken to tackle air pollution from fossil fuels, which kills over 8 million people every year, and to reduce carbon dioxide emissions, which will decide the long-term future of the climate.
But a dual strategy that also slashes the short-lived super climate pollutants offers the best, and indeed, the only hope of our making it to 2050 without suffering the climate punishment of irreversible and catastrophic impacts.
Durwood Zaelke is president of the Institute for Governance & Sustainable Development (IGSD) in Washington, D.C. and Paris, as well as an adjunct professor at the University of California, Santa Barbara Bren School of Environmental Science & Management.
Gabrielle Dreyfus, Ph.D., is chief scientist at IGSD and an adjunct professor at Georgetown University.
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