... tell them they're full of it. 2011 was the ninth hottest year on record, and those records go back 130 years. And then they might say, well, sure, but that could be coincidence. Then you look them straight in the eye, and you say: Nine of the ten hottest years on record have been since 2000.The map above shows changes from average (where the average is from 1951 to 1980). You see clearly that temperatures over land have increased almost universally. Most of the ocean temperatures have gone up as well; the one big cooler region in the eastern Pacific is due to the La Niña last year, so it's a temporary effect. Even with La Niña dropping temperatures, the overall effect is an increase in temperature. I'll note that sunspot numbers were low last year as well, which (if anything) should result in a (very) slight cooling effect too. Climate change deniers will gnash and froth -- I expect the comments to this post to reflect that, as they always do -- but the bottom line is this. The Earth is getting hotter. Human beings are at least partly to blame, and the evidence has piled up that we are mostly to blame. Not the Sun, not cosmic rays, not orbital oscillations. Humans. As I've said before, here are the facts:
The Earth is warming up. The rate of warming has increased in the past century or so. This corresponds to the time of the Industrial Revolution, when we started dumping greenhouse gases into the atmosphere. Greenhouse gases warm the planet (hence the name) -- if they didn't we'd have an average temperature below the freezing point of water. Carbon dioxide is a greenhouse gas which is dumped into the atmosphere by humans to the tune of 30 billion tons per year, 100 times the amount from volcanoes. And finally, approximately 97% of climatologists who actually study climate agree that global warming is real, and caused by humans.
Given the vast amount of evidence supporting all this, denying it is fantasy. Again, that won't stop deniers: they will obfuscate, blow smoke, and nitpick details to make them seem important. But what they're doing is fiddling while Earth burns.
Related posts: - New independent climate study confirms global warming is real - Climategate 2: More ado about nothing. Again. - Arctic ice at second-lowest extent since 1979 - As arctic ice shrinks, so does a denier claim