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Study Finds World Warmth Edging to Ancient Levels
Krishna Dagli writes to mention a decades-long study by NASA scientists. According to the research, global temperatures are reaching highs not seen in thousands of years. From the article: "One of the findings from this collaboration is that the Western Equatorial Pacific and Indian Oceans are now as warm as, or warmer than, at any prior time in the Holocene. The Holocene is the relatively warm period that has existed for almost 12,000 years, since the end of the last major ice age. The Western Pacific and Indian Oceans are important because, as these researchers show, temperature change there is indicative of global temperature change. Therefore, by inference, the world as a whole is now as warm as, or warmer than, at any time in the Holocene. According to Lea, 'The Western Pacific is important for another reason, too: it is a major source of heat for the world's oceans and for the global atmosphere.'"
If you haven't seen An Inconvenient Truth, yet, do try. Like Al Gore, it's a bit clunky, but there's a lot of truth in there and shouldn't be discounted just because you may not like the presenter.
My belief is, we'll keep right on going in this direction until we feel sufficient pain* to stop. Famine and flooding will certainly increase the likelihood of conflict. Darfur as depicted in the film was an eye opener, the severe drought which may be caused by warming now appears more likely the root of conflict as people scrabble for remaining water and land.
It may become the view that USA and Europe, have had it good long enough and they should cut down on emissions first. It will come to a head when cities like Shanghai are under water and each country is blaming the other for the fine mess things are in. Those who have dipped deepest and longest into the carbon fuels trough the will have an uncomfortable time of it.
A feeling of having made the same mistake before: Deja Foobar
http://en.wikipedia.org/wiki/Temperature_record_of _the_past_1000_years#General_techniques
It probably took you longer to post that question than it took me to find that answer.
=Smidge=
The article only actually mentions climate change within the past million years. Measuring temperatures over ththis period is relatively easily done by measuring the makeup of dissolved gas within ice deposits from the period. The gas composition is affected by the temperature at the time the ice freezes so by compiling many samples an extremely accurate climate chart can be put together.
To some extent it is also possible to measure even longer trends of several millions years using a few methods which have varying degrees (haha) of accuracy. Studying the geological effects on rock (i.e. calculating sea level height by erosion caused on rocks which were on the surface at a known point in time) is one of the most common.
More data equals more confidence. If you dredge up thousands and thousands of ice cores, mud cores or what have you, take all the data and plot a histogram of it, you usually get a nice bell shaped curve. If you've got lots and lots and lots and lots of data, which these guys do, you can safely say that the middle of the bell curve is the mean of your data.
Of course, as you mention, there is a margin of error. However, by a happy chance of mathematics, the more data you get, the more confident you become that the temperature was within so many standard deviations of the mean. The bell curve won't change shape, in fact you want it to stay the same. And if it does, that means, on average, the temperature or whatever was in and around the mean value.
Basically if you get enough data, i.e. do enough experiments, you can tell the doubters to stick their unsubstanciated opinion where the maths don't shine.
May the Maths Be with you!