Ocean Circulation May Be Shutting Down
Remember the 2004 movie The Day After Tomorrow, where fresh water from melting polar ice pours into the North Atlantic, pushing down the warm salt water and causing ocean currents there to stop flowing, thus initiating a global catastrophe?
Lots of people laughed at the premise. But if James Hansen and 16 other top climate scientists are correct, we may indeed be seeing the first signs of a complete shutdown to the circulation of the world’s oceans.
Hansen, arguably the world’s most respected climate scientist, has co-authored his most alarming study yet on what’s happening to Planet Earth, providing clear evidence that several of the ice sheets at the poles are now melting at exponential rates, and arguing that if more of them are also doing this (which is entirely likely though they’re not being studied), then dangerous amounts of fresh water will have poured into the oceans in a matter of decades, not millennia, as previous studies had indicated.
Hansen’s new study also disputes the conventional wisdom about how much time we have left to act and what are the bottom lines and tipping points. One such piece of conventional wisdom is that governments should aim to keep global warming from going over 2⁰C above pre-industrial levels. (Not that the global community is anywhere near accomplishing that.) But Hansen now writes:
We conclude that 2°C global warming above the preindustrial level, which would spur more ice shelf melt, is highly dangerous.
As to whether we could even prevent the huge West Antarctic Ice Sheet from collapsing, one of Hansen’s co-authors, Eric Rignot of NASA, concluded last year that its meltdown is probably “irreversible”. As the new study notes:
If the ocean continues to accumulate heat and increase melting of marine-terminating ice shelves of Antarctica and Greenland, a point will be reached at which it is impossible to avoid large scale ice sheet disintegration with sea level rise of at least several meters. The economic and social cost of losing functionality of all coastal cities is practically incalculable.
Paradoxically, the warming of the poles and melting of the ice actually leads to colder, not warmer, weather in North America, Europe and Asia. That’s because as the ice melts and cold fresh water pours into the oceans, it pushes down the warmer waters that flow from the tropics to the poles, disrupting these ocean currents.
Paradoxically, the warming of the poles and melting of the ice actually leads to colder, not warmer, weather in North America, Europe and Asia.One of the best known of these currents is the Gulf Stream, which flows out of the Gulf of Mexico and then up and out across the Atlantic, keeping Britain and other northerly European countries from freezing over. (It’s the disruption of the Gulf Stream that’s the premise of the movie The Day After Tomorrow.)
Indeed, there is already evidence of such cooling in the north Atlantic, as you can see from the blue patch in this diagram:
One of the effects of ocean currents shutting down would be hotter temperatures in the tropics but colder temperatures in the temperate and polar regions. And the rough winters we’ve already been seeing in the northern United States could be a portent of what’s to come. Sea levels are now rising exponentially, meaning that the loss of polar ice could double in just 10 years.
And then there’s the effect that all this melting will have on sea levels. Conventional wisdom, which has been assuming a linear process of rising oceans, suggests at most one meter of sea level rise by 2100. Hansen’s study, however, shows that sea levels are now rising exponentially, meaning that the loss of polar ice could double in just 10 years.
All of this is borne out by what another much-respected scientist in Arctic melting, Professor Peter Wadhams of Cambridge University, is seeing. In a video interview he explains:
“I’ve been measuring the ice thickness go down by 50 percent over the last 30 years. In the summer for instance, you used to see very heavy pack ice so that a ship would have great difficulty getting through it. Today, it’s more like a blue planet. It’s almost an ice-free Arctic. That’s a big change.”
More alarming still is the fact that stored right under the ice is a vast quantity of methane that’s been held in place there for thousands of years. And methane is the ultimate global warming gas: 27 times as potent as CO2.
Methane plumes are already being observed bubbling up from Arctic and sub-Arctic marshes that used to be completely frozen. And as the white, heat-reflecting ice melts, it turns to dark, heat-absorbing marshy water, thus setting in motion an unstoppable feedback loop.
Prof. Wadhams believes that within the next couple of years ice could disappear completely from this region during the summer months.
“So, this attempt to pretend that we can keep global warming below 2⁰C, which was already a pretense, is even more ridiculous. It’s certainly going to get to 4 or 5⁰C by the end of this century, which will have quite catastrophic impacts on agricultural production.”
Just a couple of weeks ago, on July 2nd, 2015, during a heat wave in East Siberia, in the Arctic Circle, temperatures reached 98.78°F (37.1°C), as hot as the desert Southwest.
If the situation continues as we’re seeing it, Prof. Wadhams concludes that “by ten years’ time, we’ll really be in the soup.” Paradoxically, shutting down industrial activity would actually have the effect, at least initially, of causing more warming, not less.
The only way of stopping the situation from getting worse (but not reducing it) would be to bring all industrial activity – all of it – to a complete halt immediately. That would mean no more motorized vehicles, electricity, Internet, coal or gas heating – none of it. But there’s a catch in that, too. Paradoxically, shutting down industrial activity would actually have the effect, at least initially, of causing more warming, not less. That’s because, as Prof. Guy McPherson explains it:
Industrial activity continually adds reflective particles into earth’s atmosphere. Particularly well known are sulfates produced by burning coal. These particles reflect incoming sunlight, thus artificially cooling the planet. [They] constantly fall out of the atmosphere, but industrial activity continuously adds them, too.
When industrial activity ceases, all the particles will fall out within a few days. As a result, earth will lose its “umbrella” and rapid warming of the planet will ensue … Termination of industrial activity will add a minimum of 1.4⁰C to the global average temperature.
As Prof. McPherson now puts it, “We’re damned if we do and damned if we don’t.” And these are just a few examples of how locked-in the situation is. Trying to deal with this or that aspect of it can trigger any number of unexpected side-effects.
A few other recent facts and figures:
Sea levels, warming of the surface and upper layer of the oceans, greenhouse gases and land temperatures all hit record highs in 2014. Glacier melt and tropical storms were also at a high. And average sea surface temperature was the highest on record.
Average global sea level was also the highest on record – 2.6 inches above the 1993 average.
Land temperatures in 2014 were the warmest, or tied as the warmest, since records began in the 1880s.
CO2, methane and nitrous oxide all saw another high in 2014. Atmospheric CO2 levels reached 397.2 parts per million, up from 354 ppm when the State of the Climate report was first published in 1990.
And since we’ve crossed various tipping points, even if greenhouse gas levels were cut immediately, the warming of the oceans would continue for thousands of years to come.
Hansen’s new study throws a huge wrench into the works of the upcoming climate conference in Paris. World leaders must now confront, among the many factors at play, the one overarching fact that the goal of holding global warming at 2⁰C that they affirmed at the Copenhagen summit in 2009 is actually a recipe for catastrophe.
They haven’t even been able to meet that goal, let alone what would be the real one. And the situation is getting exponentially worse every year.