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Scientists Agree on Global Warming
Kryptonomic writes: "This might be interesting news in the light of the previous Slashdot article on global warming. On Thursday the UN's International Panel on Climate Change released a damning report warming that the global warming is happening at a much faster rate than previously predicted. In this report the world's most distinguished meteorologists also give their unqualified backing not only to the argument that global warming is happening faster, but also that it is definitely due to human activity."
Some of the highly counter-intuitive effects (described below) of global warming may not be appreciated without an understanding of the contribution made to climate by the Earth's oceans.
Simply because the world's seawater stores millions of times more heat than the atmosphere, and the warm sea currents from tropical oceans transport some of this heat to northern continents like the USA and Europe which would otherwise be permanently freezing cold due to their northerly latitude. Warm sea currents are vital to agriculture and our continued well-being.
Yes, the warm sea currents that keep the planet warm have an Achilles heel -- sea currents stop moving if the saltiness of the seawater falls be low a critical level (the density of seawater depends on its saltiness, reduced-salt seawater won't sink as it normally does in the coldest polar regions, and without sinking seawater the ocean currents stop moving).
One of the agreed effects of increasing Carbon Dioxide emissions is that rainfall will increase in northern latitudes, diluting the seawater. In the limit dilution shuts down the warm sea currents.
The Gulf Stream is the most important warm sea current because it can alter worldwide climate by various positive feedback mechanisms. The climate and food production of the USA and Europe, for example, both depend on the Gulf Stream keeping the climate warm enough to grow crops.
The Gulf Stream is known to be sensitive to changes in rainfall over the Atlantic. Rahmstorf's bifurcation model of Atlantic thermohaline circulation is widely accepted by independent scientists. This model implies the Atlantic Ocean has only tw o stable modes of circulation -- ON and OFF. The Atlantic Ocean is currently in the ON mode with an active Gulf Stream. 100000 years ago, it went into the OFF mode when the Gulf Stream shut down causing a worldwide massive Ice Age. The model shows the likely cause of the shutdown was increased rainfall.
The Gulf Stream changes slightly in intensity from year to year, but overall its average state in recent decades is stable and active. However, the situation should be monitored closely because it is unknown exactly how much additional rainfall the Gulf Stream can tolerate without shutting down. The Rahmstorf model predicts a critical threshold of about 1Sv/yr (10^6m/yr) (sustained increase) which is ~50% above current long-term average rainfall, whereas rainfall over Northern Europe has actually been increasing only by about 2% a year over the last 20 years -- a total rise of 40% which is currently below the 50% threshold. Conclusion: the Gulf Stream looks safe now but vulnerable to future rainfall increases.
Most agricultural plants probably wouldn't survive. The summer air temperature in the US Mid-West, for example, would be just 32F(0C) which would stop all agricultural production.
The ORNL has researched the types of vegetation in the US in present-day conditions and in zero-Gulf Stream conditions.
Scroogle
Way to go, BBC! Glad to see sensationalistic journalism is alive and well in areas other than the US. Call me a troll or mod this down as flamebait if you must, but I just can't stand bad reporting like this.
Co-chairman of the panel, Sir John Houghton "The 1990's were the warmest decade in the Northern Hemisphere for the whole millennium"
That's probably true. Indulge me in speculation that August will be the hottest month this summer... Doesn't the climate vary anyway? And I'm not talking about the annual variations in temperature, or even ones in the scope of 1000 years. Think of cycles in the tens to hundreds of thousands of years folks.
The BBC's Susan Watts "It's the American people who are the chief culprits in pumping global warming gases into the atmosphere"
I like it when a news source quotes it's own reporters for use as supporting material. And as a red-blooded American, I just can't wait to get home and fire up the pollution machine I've got rigged up on my roof. Puh-leeez.
Keith Shine, meteorologist "The overwhelming majority of people accept the evidence that the climate has warmed up"
The climate *has* warmed up, at least in terms of geologic time, and I'll go wayyy out on a limb and go along with the possibility that many people accept this. I guess this is rock-solid evidence in support of whatever point the BBC is trying to make.
Dr Robert Watson, IPCC Chair "We could conceivably be over-estimating the effect of human activity on the Earth's climate, but alternatively we could also be under-estimating it"
Aha. Glad they pulled a null statement like this out into it's own colored box for emphasis. Sadly, this is perhaps the most credible quote made in the entire article.
"We know enough to say climate change is a serious environmental issue," said Dr Watson.
Finally, the voice of reason. Here's another tip: cash-flow is important to the state of your personal finances.
[picture caption] Industrial pollution is the main offender
Hold on now - isn't that a cooling tower? If chemical or particulate matter is being emitted from that, there are a few engineers with a lot of work to do. On the other hand, if all those nasty cooling towers are actually producing enough thermal energy to melt the ice caps and affect the salinity of the planet's oceans, then somebody really designed some inefficient power plants... And correct me if I'm wrong, but are those windmills I see in the background?
It's not as if the BBC needed to fill inches on a page to justify their ad rates, right? So why was this article even written? It could have been about three sentences long, and made its legitimate points better. At least I can't pick on them for mixing up the depletion of the ozone layer with all of this...