Global Warming—The Basics

Up-to-date figures from the Goddard Institute for Space Sciences at NASA, the National Oceanic and Atmospheric Administration (NOAA), and the Department of Energy (DOE) show a strong rise in surface air temperatures over the last two decades, and a continuing steady increase in atmospheric CO2 since 1800.

Click on Figures 1a, 1b, 1c, 1d (in that order), to see the progress of global surface air temperatures in 10-year intervals from 1980 to 2010 using animation slides from NASA (each slide will open in a new window):

Figure 1a (1980)

Figure 1b (1990)

Figure 1c (2000)

Figure 1d (2010)

Or you can view the entire video animation, 1880 to 2010, here.

Temperature differences on the charts run from -2 C (very dark blue), through 0 C (white), to +2 C (dark orange-red).

NASA determines surface air temperature changes by computing temperature anomalies—i.e., moves above and below the global mean for 1951-1980 (14.0 degrees Celsius, 57.2. degrees Fahrenheit). Climate scientists say that working with anomalies is more accurate than working with absolute temperatures, because surface air temperatures vary significantly over short distances while temperature anomalies represent changes that are consistent across large regions.

Another view of global warming is the record of combined land- and sea-surface air temperature anomalies from 1880 to the present, also published by NASA (Figure 2). These are the same events plotted on a global map in Figure 1, but plotted here as a monthly global mean:

Figure 2

A similar chart of just land-surface air temperature anomalies, excluding cooler sea-surface air temperatures, would show a somewhat more overheated planet. But Figure 2 still shows a robust upturn in temperatures and rebuts attempts by climate-change deniers to use cooler sea-surface air temperatures as evidence against global warming. The four related views of dramatic climate change in Figure 1, above, also represent global data of both land-surface and sea-surface air temperatures.

The history of atmospheric CO2—measured in parts per million (ppm)—goes back more than a thousand years, based on core samples from the Antarctic ice cap (Figure 3):

Figure 3

The industrial revolution gave us the sharp rise since 1800. After 1975, the track of CO2 is updated using data recorded at the Mauna Loa observatory in Hawaii (Figure 4):

Figure 4

The rise of CO2 has been accelerating: +12.5% during the first 170 years of the Industrial Revolution (1790-1960), +24.0% in just the last 50 years (1960-2010). Atmospheric CO2 is a significant contributor to global warming. The steady rise since 1960 promises continued upward pressure on atmospheric temperatures. As geologist Peter Demenocal says:

One of the things we have learned is that…climate responds very rapidly, very actively to CO2 changes. And, so, from the geologic record as a history book, we have every expectation that climate will change remarkably in our generation.

Economists call an event like the long rise of atmospheric CO2 a negative “externality”—an indirect cost in the form of an overheated and degraded environment that harms everyone, but not in the form of a money cost to those who profit and benefit directly from the processes of extracting, marketing, and consuming fossil fuels. It’s just another way of saying that we have never paid the full cost of the energy we use, except now as we are all affected by global warming.


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