Alan Zendell, August 6, 2021

Climate change is a long process whose effects vary considerably both geographically and over time. The latest phase of climate change, popularly referred to as global warming, has been producing record high temperatures and storms that increase in violence and frequency in some places, and calm, lovely summer days elsewhere. On most days, there are many more high temperature locations than low ones, causing an average annual increase in global temperature.

One reason there is so much controversy over global warming and so many people willing to believe profiteers who want to convince them it’s not happening is that the place they live might have perfect weather on any given day. From that vantage point, it’s impossible to grasp the global impact. It’s much like election campaigns. If those who profit from spewing carbon into the atmosphere spend enough money trying to convince people that climate change is a left-wing hoax, many of them will be willing to believe last week’s record heat wave was just an aberration.

Actually, there’s a lot to worry about, and it’s not only more hurricanes and tornadoes, record droughts, raging wildfires that consume more forests and homes every year, and rising sea levels. If all that weren’t enough, there’s another issue on our horizon that could catastrophically affect all of us. The problem is well-known to scientists and oceanographers who’ve warned us about it for decades. Most people who hear it think it’s just another disaster scenario designed to scare us into changing the way we live, but it’s very real and even more of a threat than was thought a few years ago.

The issue is the systems of Atlantic Ocean currents that control temperatures in the northern hemisphere. That includes us. Ocean currents redistribute heat from the warmer regions in the Caribbean all the way north to Prince Edward Island in Canada, but global warming is making those currents unstable. (The link is to an article on CNN’s website, this morning, that explains the problem and reports on a just-published research report that is alarming scientists.)

Simply put, “The Atlantic Meridional Overturning Circulation (AMOC) — which the Gulf Stream is a major part of — helps maintain the energy balance in the Atlantic Ocean. It is often described as a ‘conveyor belt’ that takes warm surface water from the tropics and distributes it to the north Atlantic. The colder, saltier water then sinks and flows south.” The process depends on the fact that salt water is denser than fresh water, but melting ice caps and glaciers have been dumping fresh water into the Arctic Ocean at an increasing rate, part of a normal cycle of climate variation, but one that industrialization has accelerated.

As more fresh water mixes with northern oceans, their salinity decreases. Scientists have long warned that if this continued, the Gulf Stream would eventually become unstable and cease to flow. It’s the kind of esoteric warning that’s easy to dismiss, but the consequences of the loss of the Gulf Stream would be catastrophic to the United States and the world.

The Gulf Stream maintains the temperate climate of all of northeastern North America. If it were to suddenly cease flowing, the entire northeastern United States would be plunged into an endless winter. The result would be the formation of icepacks and glaciers from Maryland to Maine and north into Canada. Every northeastern city north of Richmond, Virginia would become uninhabitable within a few years – some scientists believe it could happen in as few as five.

According to today’s report, a “study, published Thursday in Nature and Climate Change, warned of an almost complete loss of stability of the AMOC over the course of the last century. Researchers say it could be close to a collapse … though the threshold for such a collapse is still uncertain.”

The 2004 film, The Day After Tomorrow exploited this phenomenon. The film was viewed by most people as just another disaster movie, because the specific situation it described, a virtually instantaneous collapse of the forces that warm us, didn’t seem believable. The movie portrayed a highly unlikely (though possible) scenario, but the result it showed, everything north of Washington under ice in just a few years is a very real possibility.

Between 2004 and 2007, Kim Stanley Robinson, a highly respected author of speculative fiction based on hard science, published the trilogy, Science in the Capital (Forty Signs of Rain, Fifty Degrees Below Zero, and Sixty Days and Counting) that chillingly and brilliantly described how the United States would be affected by the loss of the Gulf Stream.

Twenty years ago, scientists were already seriously worried that if the polar icecaps continued to melt, the loss of the Gulf Stream would eventually follow. We’re already close to the tipping point, and there is little reason to believe we won’t cross it. The ice caps are melting faster today than they have since the last ice age.

This is neither a joke or nor a scare story. It’s real, hard science. Take it seriously.