Global Warming
Or, more accurately, global climate change.
Some sites like junkscience.com are basically running smear campaigns trying to debunk global warming. Their articles all come from really sketchy sources, and most of their reasoning comes out of the ether, or really sketchy data (like that one average-world-temperature graph for the last 200 years). So, here's the scoop from a thread in the snopes.com forum:
James writes:
...convincing me that the Earth is warming is a far different thing than convincing me that the Earth is warming due to man-made sources. Why should the temperature of the Earth a hundred years ago be regarded as the "correct" temperature for the Earth. There is a lot of evidence the the centuries between 1200 and 1800 were experienced a cooling trend, the the 1800's being especially cold. There is plenty of circumstantial evidence that around the year 1000 the Earth was much warmer than it is today. How do we know that the warming trend isn't part of a natural cycle of warming and cooling, based on feedback loops that far exceed the span of a human lifetime? It is certainly foolish to argue that the Earth hasn't undergone much more extreme temperature swings than what's happening today. We are no where near the chills of an ice age or the balmy highs from the age of the dinosaurs. Isn't it chauvanistic to regard Earth's recent temperature (the last few hundred years or so) as the "normal" temperature? So, I'm in a wierd middle camp. All the people who insist that the world isn't warming seem to me blind to overwhelming data, and politically motivated to deny man-made warming because of the economic and political consequences. But many of the people who insist it is warming seem just as politically motivated, and turn me off by stating that the case is closed, that everyone knows that the Earth is warming due to man-made causes and anyone who thinks otherwise is just a cynical tool of the oil companies.
Although, speaking of cynical, I must admit, during the colder parts of winter, I sometimes go out and drive unnecessary errands, just in case I can speed the process along. I can see a lot of advantages to moving the beach front about fifty miles closer to my house.
Sub-Contractor responds:
Ah, arguments in academia. I'd almost forgot how vicious they could get. (And why I enjoy shooting nails now. :P ) From what I can tell, the big graph that everyone points to for proof of global warming has potentially serious flaws. Okay...I had a question about it when I first saw it in an ecological history course. If the data were that blatant, there wouldn't have been any debate. So it goes on, but not about the temperature increase -- just the causes. The argument is based on a climatological theory that the Earth has gone through a cycle of warming and cooling over the past several hundreds of thousands years, possibly starting when the Himalayas were formed. The cycles run 10,000 or so years where the temperature rises to an altithermal, then cools to an ice age and warms again. This cycle also runs in conjunction with the slow oscillation of the Earth's axial tilt between 21.6 to 24.6 degrees over 41,000 years. Currently both the axial tilt (23.44 degrees) and the average temperature are both decreasing. The "hockey stick" jump in temperature would run contrary to the established cycle. The temperature should not be rising again for several thousand years. The argument that the rise is from modern emission of fossil fuels is partially predicated on this graph and in conjunction with ice core samples from the altithermal time period being used to study atmospheric content. Basically, trace gases like CO2 are approaching or exceeding levels from the older hot time.
This may lead to premature heating and a greater loss in ice caps than before…possibly upsetting the cycle completely. Also the release of more fresh water into the oceans this early in a cycle may slow or stop the deep currents in the ocean, leading to highly unstable weather (record highs and lows in successive months during the same season).
Or it all could be wrong, such is science.
ULTRAGOTHA adds:
Global warming, whatever the cause, does not mean that every place on the globe will be warmer. In some cases, it means the opposite. For example, the southwestern areas of Ireland and parts of England are warmer than they 'normally' would be due to influence from the Gulf Stream that brings warm water up the Atlantic close to those areas. Global warming may melt enough of the Greenland glacier to force the Gulf stream away from those areas, and make them quite a bit colder than they have been. That's just one example. Plus you've got El Nino and variations in the Jet Stream, and other influences, that can make local areas colder or warmer, regardless of what the overall global temperature is doing. I'm with James. I think the evidence that the Earth is warming up is indisputable--the Arctic Circle is unfrozen for far longer than it used to be, the Greenland glacier is melting, the Antarctic glaciers are breaking off (in Rhode Island-sized chunks) and melting. That doesn't mean that all our carbon dioxide is causing it, though.
On the other hand, I can't see any reason why cutting CO2 emmissions would be a BAD thing. And I don't like the US unilaterally deciding to pull out of a treaty whenever we feel like it. Thus I support Kyoto, though not necessarily because I believe it will influence Global Warming.