Thursday, June 02, 2011

Global Warming Our Greatest Threat

It wasn't the cartoon by Tom Tomorrow (below) that inspired this post, it fell into the inbox only today. But for a couple of days I have been trying to cobble a post together as a result of few other article alerts, two of which I list here.

The Sky Really Is Falling
31 May 2011
by Chris Hedges

The rapid and terrifying acceleration of global warming, which is disfiguring the ecosystem at a swifter pace than even the gloomiest scientific studies predicted a few years ago, has been confronted by the power elite with two kinds of self-delusion. There are those, many of whom hold elected office, who dismiss the science and empirical evidence as false. There are others who accept the science surrounding global warming but insist that the human species can adapt. more truthout

Global warming: Bleaker and bleaker
30 May 2011
New figures show we are still hurtling towards dangerous climate change - at a time when policymakers are running out of ideas

Sometimes a quotation really does say it all. As chief economist of the International Energy Agency, Fatih Birol is not given to overstatement – so his comment in our paper today that the latest figures on greenhouse gas emissions are "the worst news" should be taken seriously. It is not just that the statistics showing another record leap in carbon output – 30.6 gigatonnes of CO2 over 2010 – to make the highest annual total in history are grim. They also come at a point when the old centrist certainties about how to tackle climate change are palpably out of date, and yet no new ideas have come along as replacement. more gruniad

In spite of all my recent coverage regarding nuclear power and its deadly and unacceptable legacy, the biggest single threat we face today by far, is the release of fresh melt-water due to global warming.

Although other global ocean currents would also be affected, it is the threat to the Gulf Stream, due to de-salination, that is of the greatest concern. In a nutshell, if the thermohaline circulation (conveyor belt) of the Gulf Stream ceases, we are doomed.

Europe will start to experience the type of severe winters that are comparable with other regions of the globe that share the same latitudes. My own line of latitude in the UK for instance, runs through the southern half of Hudson's Bay, an area one could hardly described as temperate. But the implications and consequences of such an event are far greater than, a bit of a cold spell for Europe, button up your overcoat; it will herald the onset of climate change of cataclysmic proportions.

This short video explains the general situation. The first three minutes only, unless you want to bring Veganism into the equation.

Below: BBC's The Big Chill. 4mins

This 2002 article is as good as any that I have come across in explaining the situation.

A Current Controversy: Is Europe About To Freeze?
Feb. 22, 2002

One of the odd possibilities that could emerge from global warming is that much of Europe, robbed of the ocean current patterns that help keep it warm, could rather abruptly enter a deep freeze and have a climate that more closely resembles Alaska than the modest temperatures it now enjoys.

Researchers from Oregon State University explored this potential phenomenon, and the fluctuations in "thermohaline circulation" that could trigger it, in an analysis to be published Thursday in Nature, a professional journal. It's by no means certain that climatic changes of this magnitude and speed will come to pass, the scientists say, but even the reasonable possibility that they might are a cause for serious concern.

"To answer difficult questions such as this we depend a lot on our computer models, and in this area different models reach different conclusions," said Peter Clark, an OSU professor of geosciences and one of the world's leading experts on glaciers and prehistoric climate changes.

"What is fairly clear is that if the ocean circulation patterns which now warm much of the North Atlantic were to slow or stop, the consequences could be quite severe," Clark said. "This might also happen much quicker than many people appreciate. At some point the question becomes how much risk do we want to take?"

The big variable in this particular equation, Clark said, is whether or not changes in global temperature and precipitation patterns might affect a gigantic conveyor belt of warm, less-salty surface water that moves from the tropical Atlantic Ocean until it finally becomes so cold and salty in the far north Atlantic that it sinks, moves south and continues the circulation pattern.

This process, called thermohaline circulation, only happens in two regions of the Earth's polar areas. But it is responsible for much ocean circulation, including the critical currents that help keep parts of North America and Europe far warmer than they would otherwise be, considering the far north latitudes at which they lie – most of Great Britain is at the same latitude as central Canada.

This circulation process, researchers say, is not inevitable. Research suggests it may have fluctuated or even stopped numerous times in Earth's distant past, and that it's especially sensitive to moderate increases in temperature or influxes of fresh water. The same very cold, very salty water that sinks in the far North Atlantic Ocean simply won't sink if it's just a little bit warmer or a little bit less salty. And at various times, it appears these changes have happened not in geologic terms of thousands of years, but rather decades.

"This system does not respond in what we call a linear manner," Clark said. "Once you start putting on the brakes, this circulation pattern could slow down faster and faster and eventually stop altogether."

Research has found that some of the Earth's most rapid climatic shifts – up to 15 degrees in decades or less – have in the past occurred during glacial periods, when large ice sheets advanced from the polar regions as far south as New York City, among other places. Some scientists have even theorized that the wild temperature fluctuations of the last ice age may have retarded the evolution and development of humans as a species, as they struggled to cope with rapidly changing conditions.

We are now in an "interglacial" period that, in theory, may have less volatility, but could also be coming to an end.

Global warming will simply delay the inevitable, Clark said, because it actually should be about time for Earth to enter its next ice age. There's a fairly well defined pattern of about 10,000-year-long interglacial periods followed by 90,000-year-long ice ages, and the current interglacial period is already more than 10,000 years old.

"At this point we just aren't sure what to expect in terms of climatic volatility," Clark said. "But the more we learn about them, it becomes clear that these thermohaline circulation patterns are quite sensitive to temperature and influxes of fresh water, such as you might get with changing precipitation patterns triggered by global warming, not to mention melting ice caps or glaciers."

So the paradox, the scientists say, is that the same greenhouse effect which might make the Earth warmer, overall, could have the opposite effect on much of Europe by slowing or shutting down the warm ocean circulation patterns on which it depends.

"Most, but not all, coupled general circulation model projections of the 21st century climate show a reduction in the strength of the Atlantic overturning circulation with increasing concentrations of greenhouse gases," the researchers said in their report in Nature. "If the warming is strong enough and sustained long enough, a complete collapse cannot be excluded." This prospect – the collapse of the thermohaline circulation patterns that dictate its climate - has raised enough concern, Clark said, that Great Britain recently launched a $40 million research program to analyze this phenomena and its possible implications. And the National Academy of Sciences recently issued a report that made reference to an "inevitable surprise" of "climate changes with startling speed."

At this time, Clark said, some of the best potential to improve the ocean and atmospheric computer models that could help resolve some of these questions about future climate lie in studies of the distant past. Ice cores from Greenland glaciers have been instrumental in this work, he said, providing a look backwards at climatic conditions more than 100,000 years into the past, and work in that area will continue. Science Daily found at a big page of links.

A comprehensive article on the subject of coal.

Down With Coal! The Grassroots Anti-Coal Movement Goes Global


Anonymous said...

Half the Great Barrier Reef has disappeared in past 3 decades.

Himself said...

Were fucked.

Nice animal pics though, and now I know where to find the Atlantic Conveyor post.

Ta Chuck.