WunderBlog Archive » Dr. Ricky Rood's Climate Change Blog

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By: Dr. Ricky Rood, 4:11 AM GMT on February 14, 2007

In my guest blog on Jeff Masters' January 31, 2007 uberblog, I stated that the climate change problem touched all parts of society; hence, it is controversial. Ultimately, however, we have to pull something out of that controversy. It is my intention not to present, simply, sound bites; it is my intention, with your help, to develop, a few hundred words at a time, a coherent body of work. My effort starts from my foundation, the scientific evidence of climate change and the predictions of future climate change. As the discussion from the previous blogs shows, we branch quickly beyond the scientific realm. We are immediately faced with how do we evaluate the scientific basis--how do we assimilate this into what we believe and what we want to believe? Now back to the physical climate.

Jeff ( February 12, 2007 ) and I have both shown plots of temperature as a function of time. These show that averaged over a wide region that the temperature is increasing. The fact that average temperature increases raises the confidence that the trend is real; we are not just picking out a single place to make a claim. Figure 1 shows model-predicted temperature changes from "Climate Change 2001".

Figure 1.Predicted changes in Earth's surface temperature in 2100. This is from "Climate Change 2001." Scenario B2 refers to the assumptions made about future emissions and is described as one with "increased concern for environmental and social sustainability."

This is one of several calculations that show the same pattern of temperature changes. It is qualitatively the same as in "Climate Change 2007." (It's just easier to link.) The warming is predicted to be greater at high latitudes, especially in the northern hemisphere. The continents warm faster than the oceans. These patterns reflect the differences between the distribution of land and water and ice.

Figures 2 and 3, below, show the observed difference of two individual years from the average calculated between 1961 and 1990. This averaging period is a time when average surface temperatures were increasing; hence, the figures below are not compared to some period chosen because it was cold.

Figure 2.
From "State of the Climate (NCDC):" Difference, the anomaly, between the annual averaged temperature in 2005 and an average calculated from 1961 to 1990.

Figure 3.
From "State of the Climate (NCDC):" Difference, the anomaly, between the annual averaged temperature in 2006 and an average calculated from 1961 to 1990.

Figure 2 shows the difference of the year 2005 from this average. Studying the figure, what is most prominent is warming in the north, warming over the continents. Figure 3 from 2006 has a region of cooler temperatures centered on Siberia. In any given year there are likely to be cooler spots and warmer spots. Still, these figures, are dominated by red dots, warmer than average, an average which by most standards was, itself, warm. The dots show more warming over land than ocean, greater warming at high northern latitudes. If you were to average together, say, the last ten years and form a difference from the average, the warm anomalies will become even more dominant.

This is a simple example of the idea of "fingerprinting." We have the geographical distribution of the warming signal predicted by the models--Figure 1. We have the emerging shape of the measured warming in Figures 2 and 3. Questions that are posed include: How alike are the observed and predicted changes? If they are alike, what is the probability that they are alike because they are the same (with an estimate of uncertainty)? Is it simply a coincidence? Every set of fingerprints we find in the observations that match fingerprints from the model predictions strengthens the likelihood that the predictions are correct--not simply coincidence--not simply contrived by engineering towards a solution. "Climate Change 2007" concluded that "warming of the climate system is unequivocal."


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.