Sunday, January 11, 2009

A Global Warming Paradox

I've seen some posts in the blogosphere lately stating that the colder temperatures of 2008 constitute proof that global warming is a myth. Of course, those same folks never believed that the record warm years in the 1990s consituted proof of anything. Nor did they pay any attention to the prediction by scientists at Woods Hole Oceanographic Institute that global warming could trigger another little ice age in parts of North America and Europe.


How can global warming trigger an ice age, you ask? By interrupting the Great Ocean Conveyor -- a set of ocean currents that transfer heat from the equator to the arctic regions. Basically, warm and salty (from evaporation) ocean water makes its way north, where it becomes cooler and fresher (from river run-off and precipitation). As it cools, it sinks, although the desalination slows the sinking (since salt water is denser than fresh water).

It is the force of this cold water sinking below the warmer water that drives the conveyor belt of currents. If the freshening of the water is sufficient to counteract the cooling, it won't sink, and the current will shut down. The scientists at Woods Hole noted that the rapidly melting arctic glaciers would dump larger-than-usual amounts of fresh water into the north Atlantic, and this could interrupt the Great Ocean Conveyor.

I first read about this several years ago. As Wisconsin's winters became milder and milder, forcing ski resorts to close early and cancelling the American Birkebeiner, I waited for the other shoe to drop. Last winter, as I was shovelling snow for what seemed like half my waking hours at home, I wondered if it was starting to happen. I searched for recent articles on the phenomenon.

Scientists at Great Britain's National Oceanography Centre detected in 2005 a significant reduction in warm currents from the Gulf Stream between 1992 and 1998. They were surprised by the findings, because they thought that such a reduction should result in cooler temperatures in Great Britain and Scandinavia. As of 2005, they hadn't seen it yet. They may be seeing it now.

Those wanting more information about this phenomenon should check out this 2002 research paper entitled "Abrupt Climate Change: Invevitable Surprises." And think of alternative modes of transportation.

5 comments:

Deekaman said...

I'm unwilling to believe Global Warming either way. Yes, I'm a skeptic, but I'm also unwilling to rule out the possibility that AGW does exist. I'd claim there is sufficient evidence to indicate this is much more complex than we'd like to think and that solar irradience drives cycles much more strongly than anything we mere mortals can do. And, oveer my 52+ years, I've heard "the sky is falling" many times and it never has. The air, water and land are cleaner than they were when I was a child (point is "Chicken Little, not AGW).

All that said, the biggest piece that gives me pause is the way the AGW believers treat it like a religion and anyone who questions them are heretics.

Further, many noted scientists, some of whom have been part of the IPCC are now questioning AGW. That speaks volumes. At least enough for me to question.

Deekaman said...

But I ramble...
;-)

Ordinary Jill said...

Well, you're certainly entitled to believe whomever you wish. I agree that the global warming skeptics should have the opportunity to make their case without being automatically ostracized. Keep in mind, however, that there are scientists in South Africa who still insist that AIDS is not caused by the HIV virus, despite overwhelming evidence to the contrary (and those scientists had disproportionate influence over the policies of Thabo Mbeki, because they told him what he wanted to believe). In this country, there are still people who claim that autism is caused by vaccines, although numerous recent studies have thorougly debunked that myth.

Deekaman said...

Significant differences exist between your examples and AGW. There is no evidence that HIV does not cause aids and no evidence that vaccines cause autism (and even if their was, I'd take the autism risk, rather than the polio risk, having grown up at the end of polio's scourge). There is significant evidence that the AGW theory is wrong. Much evidence indicates that CO2 is a lagging factor, not a leading factor. Further, there significant evidence that glacial retreat is more a factor of low precipitation as warming.

Again, note that I say evidence, not "proof". The scientific method involves developing a theory based on evidence. The theory is tested...and tested....and tested....until proven wrong for a particular set of circumstances. I find it odd that "scientists" spend all their time trying to "prove" AGW when it is impossible to prove a theory right.

There are many red flags to AGW. These are but a few.

Jimi5150 said...

To me, what this proves, is how little we actually know about climate change. Along with el nina and el nino, little is actually know about the ocean's role in much of this. To date, little, climate-wise, is cooperating with computer models. Oceans are one reason why.