Dr. Colin Evans explains climate and weather by asking viewers to imagine walking their dog across the park using a leash that’s growing longer
October 14, 2023
Around 180 people registered for the recent Presbyterians for Earth Care webinar “The Climate Crisis: Where are we in 2023?” Dr. Colin Evans, a post-doctoral research associate at the Northeast Regional Climate Change Center at Cornell University, spoke and answered questions afterward. Watch the webinar, hosted the Rev. Bruce Gillette, moderator of PEC, by going here.
Other nearby planets aren’t equipped for life the way Earth is, Evans noted. Venus, which has 92 times the atmosphere that Earth does, is 870 degrees both day and night because of “runaway greenhouse gasses.” Mercury has no atmosphere at all and temperatures from 300 degrees below zero to 800 degrees above zero, as measured in Fahrenheit. “Miraculously, we live on this Blue Marble,” Evans said.
Weather is not climate, but weather is dependent on climate. Evans likened that to using a 10-foot leash to walk your dog from point A to point B in your local park. The dog does circles and stops and sniffs, “but ultimately you are leading the dog,” Evans said. “Weather follows along with what the climate is doing, but there’s a large variation in what weather can do. As climate warms, the dog’s leash is getting longer, and so we will see more variations and more extremes.”
If emitting carbon dioxide into the atmosphere is a problem, so is emitting methane, which is 25 times stronger, and nitrous oxide, which is 10 times stronger than methane.
There are also natural drivers of climate change, Evans said. One’s called eccentricity, the shape of the Earth’s orbit, which is elliptical. That works in 100,000-year cycles. Another is the tilt of the Earth, which operates in 41,000-year cycles. In addition, there’s an axial procession by which the Earth wobbles like a spinning top that’s slowing, which follows a 26,000-year cycle. All three-impact climate, as does the “great ocean conveyor belt,” but that process takes a millennium. Plate tectonics is another contributing factor, but that takes millions of years. “They are all way too slow to account for what we are seeing now,” including the recent news that July has been declared the hottest month in recorded history.
While we’ve seen devastating flooding in Vermont, record temperatures in cities around the world and the ice mass in Greenland steadily decreasing, what concerns Evans the most is the dwindling volume of ice in the Antarctic Sea. “It’s so abnormally low that scientists who specialize in studying it don’t know how to account for it,” Evans said.
Ocean water near the Florida Keys has recently topped 100 degrees. “I can’t overstate how much energy it takes to warm up the ocean,” Evans said. That warming can have devastating impacts on marine life, Evans said.
There are hopeful signs, too. Deforestation in the Amazon River basin has dropped 34% under Brazil’s new president. Nearly 500 American communities now officially support emission reductions and climate mitigation. Egypt is set to build the largest wind farm in Africa, and for the first-time last year, European Union wind and solar projects generated more electricity than gas-fired plants. In this country and elsewhere, the demand for electric cars is booming. U.S. sales are expected to leap 35% this year after a record-breaking 2022. Gross Domestic Product in the U.S. is growing even as the nation is working to cut its emissions, which some climate change skeptics had said was impossible.
Now many who are concerned about climate change are also fighting for climate justice, Evans said, “connecting the climate crisis to the social, racial and environmental issues that are all entangled.” He and others note that “climate change disproportionately affects those with the least amount of responsibility for the climate crisis … As an affluent country, we can take responsibility for the amount of carbon dioxide we have put into the atmosphere, and we need to hold our leaders accountable for the promises they have made.”
Evans told one attendee that “many climate scientists are of the opinion we won’t reach any [cleaner air] targets without some sort of air capture technology,” which unfortunately now produces more emissions than it’s able to extract, Evans said. Still, it’s “game-changing level technology that a lot of people are working on.”
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