As a new school year starts, let’s update our understanding of climate change. Here on our idyllic North Fork, we suffer from a malaise that I’ll call “back porch, present day myopia.” We see the reports of intense heat waves, droughts and massive flooding setting records worldwide but since we don’t see it here, it doesn’t seem real. Scientists tell us to worry about 2050 or 2100 but it’s almost impossible to relate to such distant dates. Students, you’d better start listening.
It‘s an indisputable, measured fact that the Earth has warmed by almost two degrees Fahrenheit since 1750. It’s also unequivocally true that this warming is caused by human activities, primarily the burning of fossil fuels. No serious, informed person disputes these facts — and facts are real; they exist whether you believe in them or not.
Scientists worldwide have warned us repeatedly that human emissions of greenhouse gases constitute a climate emergency. The physics is straightforward: Emissions of GHGs cause global warming, which causes climate change. Until emissions stop, Earth will continue to warm. Unfortunately, studies released this summer indicate that scientists may have underestimated the danger.
Recently, the American Meteorological Society released its 2021 State of the Climate report, and the data is worrisome. According to the report, Earth’s atmospheric concentrations of GHGs (carbon dioxide, methane and nitrous oxide) rebounded in 2021 to the highest levels on record. Ocean heat content and global sea level rise were the highest on record and Earth’s surface continued to warm, placing 2021 among the six warmest years on record.
Then, the National Oceanic and Atmospheric Administration released its 2022 Sea Level Rise Technical Report. NOAA projects that sea levels on the East Coast of the U.S. will rise 10 to14 inches in the next 30 years, which equals sea level rise over the last 100 years (1920-2020). Perhaps of greater concern is this quote: “Current and future emissions matter. About 2 feet of sea level rise along the U.S. coastline is increasingly likely between 2020 and 2100 because of emissions to date. Failing to curb future emissions could cause an additional 1.5-5 feet of rise for a total of 3.5-7 feet by the end of this century.” A potential total sea level rise of 3.5 to 7 feet by 2100 if emissions continue unabated? Wow!
Then, a study reported in Nature Climate Change notes that the Greenland ice sheet, currently one of the leading causes sea level rise, is in a state of partial collapse that will result in the melting of over 3%of the ice sheet. This massive ice loss is inevitable — even if we stopped all greenhouse gas emissions today. That much ice melt alone is capable of triggering nearly a foot of global sea level rise. Although the time frame of this melt is currently indefinite, the authors suggested that much of it could play out by 2100.
If that news isn’t bad enough, a report in Nature Briefing discusses a phenomenon known as Arctic amplification. For years, scientists believed that the Arctic was warming twice as fast as the rest of the planet. But the new study reports that “during the last 43 years the Arctic has been warming nearly four times faster than the rest of the globe. ” This is particularly disturbing because Arctic warming directly influences our weather, as well as two important amplifying feedback loops that intensify global warming: the ice-albedo feedback and the permafrost-melt feedback. As the Arctic warms, sea ice melts, exposing the darker ocean waters, reducing Earth’s albedo (reflectivity to solar radiation). Sea ice reflects about 90% of the sun’s radiation back to space without warming the Earth.
In contrast, the exposed ocean reflects less than 1% of solar radiation. This low albedo means the oceans absorb about 93% of incoming solar heat, causing additional global warming. The second feedback, melting permafrost (permanently frozen earth), exposes organic matter to decomposition by bacteria, releasing both carbon dioxide and methane, potent GHGs that intensify global warming.
Fearing apathy, I can’t help but think of the three monkeys sitting in a row covering their eyes, ears, and mouths. For too many Americans, those monkeys represent “see no facts; hear no facts; speak no facts.” But facts are real and no blindfold will prevent Earth from warming. The bill is coming due and you students are going to have to pay it.
The good news: As soon as we reduce emissions of GHGs to net zero, global warming essentially stops. Net zero emissions means that any new emissions are balanced by GHGs removed from the atmosphere. Getting to net zero emissions in time to prevent a catastrophe in your lifetime requires the will and commitment to act. Students, the ball is in your court.