Modelling's power confirmed, againModelling complex systems, such as our planet's global climate, isn't about predicting exactly what is going to happen. That's just too hard. But it can give us a much better idea of what is likely to take place than if we don't try to build models and just make informed guesses. Still, if you've been making predictions for a while, it pays to go back to your early models and compare them to what actually happened to get an idea of how accurate they were.
That's just what climate scientists did in a recent paper published in Nature Geoscience. Models based on data gathered up to 1996 were compared with actual climate data since that year, and the results show that "scientists accurately predicted the warming experienced in the past decade, relative to the decade to 1996, to within a few hundredths of a degree." Take that, 'climate skeptics'.
The Guardian writes:
The study is the first of its kind because reviewing a climate forecast meaningfully requires at least 15 years of observations to compare against. Assessments based on shorter periods are prone to being misleading due to natural short-term variability in the climate.
The new research also found that, compared to the forecast, the early years of the new millennium were somewhat warmer than expected. More recently the temperature has matched the level forecasted very closely, but the relative slow-down in warming since the early years of the early 2000s has caused many commentators to assume that warming is now less severe than predicted. The paper shows this is not true.
In other words, not climate trend is perfectly smooth, and sometimes when there's a higher-than-predicted amount of warming for a few years and then a reversion to the mean, it can look like a slowdown even if the long-term trend is the same.