What sort of error? How big? Here's what happened. This is from Wired.com:
Thought 1998 was the warmest year on record in the United States? That's what Al Gore acolytes have been telling us.
Nope. It was 1934, according to newly revised figures from NASA, released quietly. The error is embarrassing
Ah, well that changes things, doesn't it? They sum it up this way:
The data involved temperature measurements made at weather stations in the United States. Back in 2001, scientists the National Oceanic & Atmospheric Administration realized that some data was being skewed by stations making recordings at different times of day, or being located in once-rural areas that have become heavily urban, causing local temperatures to rise.
They published the a formula to account for the discrepancies. Generally, this lowered the average temperatures recorded. However, NASA's weather-crunching programs weren't updated. As a result, subsequent NASA temperature recordings were incorrectly high, and some earlier data needed revision downwards.
How big was the mistake? About .15 degrees celsius, or .3 degrees fahrenheit.
Now, this isn't a huge number, but it's enough to make a difference -- if, that is, the mistake applied to the whole planet. But the mistake involved only the United States, which covers but a small fraction of the globe. [emphasis added]
Again, the corrections were for data in the US only, not globally. Something the otherwise erudite editorialists working for Dickiecougarmellonscaife utterly failed to inform its readers.
We don't have the science to predict accurately what the climate will be in 50 or 100 years. Now we find out that NASA didn't get the previous temperature averages right.
In comparison to making climate forecasts, that ought to have been pretty simple.
Here's NASA's graph of the data. See that little green line? That's the correction.
And remember that's just for temperatures in the US. Here's some data for global temperatures.
Notice anything? Like the general upward trend from, say, 1910 on? Granted, things reversed themselves from the mid-40s to the mid-60s, but look at what happens after.
Yea, there's doubt about that the temperature's rising.