Riddle me this …
by Tamino [this guy is a national treasure!], Open Mind, December 7, 2009 · 52 CommentsThose who are in denial of global warming insist that the last decade of global temperature contradicts what was expected by mainstream climate scientists.
Here’s global temperature data from NASA GISS before the 21st century, for the time span 1975 to 2000:
I’ve computed and plotted a trend line using linear regression. In addition, I’ve plotted dashed lines two standard deviations above and below the trend line — we expect most of the data to fall within these dashed lines. Finally, I’ve projected those lines out to the present day.
That’s what mainstream climate scientists expected to happen.
Here’s what actually happened.
Gosh. What actually happened is exactly what was expected. Exactly. By mainstream climate scientists. You know, those folks who keep telling us that human activity is warming the planet and that it’s dangerous.
What’s that? You don’t trust NASA GISS? You think they faked it, or it’s all just urban heat islands? How about satellite data from RSS — there’s no urban heat island effect there!
Hmm. What actually happened is exactly what was expected. Exactly. By mainstream climate scientists.
Don’t trust the people at RSS? How about the denialists’ favorite data, satellite estimates from UAH?
We’re only 10 years into the 21st century, but so far, global temperature has done exactly what was expected by mainstream climate scientists. Exactly. You know — those folks who keep telling us that human activity is warming the planet, and that it’s very dangerous.
This is undeniable. Unless of course you’re in denial.
Yet people continue to deny it. They tell you it’s all a hoax, and to support that idea they repeatedly claim that the last decade of temperature data contradicts global warming.
Riddle me this: why can’t they get something this simple right?
UPDATEKevan Hashemi submitted this comment:
You picked the period 1980 to 2000 do you would get a positive slope. Why not fit a line to 2000 to 2010? Because it shows a negative slope and you don’t want that? Well, that’s precisely the point skeptics are making: if you look at the last 10 years, the trend is zero or down. You choose your own 20 years to show the trend is up. If you chose 1940 t0 1980 the trend would be down. In 1999 climate scientists told us the world would warm up over the next ten years. It didn’t.You are wrong on all counts.
The trend lines from 2000 to 2010 (actually to the present since 2009 hasn’t ended yet) are all positive:
More to the point, the uncertainties in trend estimates using just data since 2000 are much larger than the trend estimates themselves. Attempting to delineate the climate trend using so little data is a fool’s exercise.
That’s the point. They’re trying to fool you.
As for “warming since 1999″:
Finally — with GISS data I started at 1975 because that’s a natural turning point in the temperature trend, and data since 1975 actually does enable us to estimate a trend with sufficient precision to be useful (unlike your suggestion of starting with 2000). For RSS and UAH data I started at 1979 because that’s all the data there is.