One of the central questions in climate science has been: “Is the climate warming?”
While the considered answer has been “Yes” for many years, the way science works is that prior conclusions are always challenged when new data are acquired. Let’s look at 2012 and some recent temperature data for the 48 contiguous states and see how that fits with earlier data.
The graph here from the National Climate Data Center tells an interesting story. The nine-month (January to September) average temperature data since 1895 were used in order to see how 2012 compares. The data show a clear upward “Trend” (solid straight line) of about 1.390F per century. The left-hand axis shows this change from about 55.50 to almost 570F. The right-hand axis is in degrees centigrade.
As we can see, the data for 2012 are almost off the chart and far higher than any measurements in the last 117 years.
What is also interesting is the up-and-down annual temperature changes over this period of time. This is the normal “weather” variation we see on a month-to-month or year-to-year basis. This is why climate scientists look for data over longer periods of time in order to arrive at a better understanding of what is going on.
Another aspect of climate science is to evaluate how this information dovetails with other data. The information on minimum ice volume data in the Arctic also supports that warming is occurring.
The bar chart here is based on data from University of Washington PIOMASS project and plotted by L. Hamilton of University of New Hampshire. It shows data from 1979 to 2012 as measured in September when ice is at its minimum. The results are almost startling as the drop in ice volume seems to be accelerating and is only about 20 percent the amount it was 33 years ago.