Science does not usually advance in quantum leaps. More often it's a matter of small steps. So it is with the latest report from NASA on global climate change, which concludes that the Earth's 12-month running mean temperature reached its highest point on record in 2010.

By itself, that doesn't mean much. The authors of the scientific paper that presents the findings say that. Climate is the study of conditions over long periods of time, and the hottest year is simply a snapshot in a much larger panorama.

Nevertheless, this latest finding does suggest that global warming, when measured in terms of decades, not single years, "is continuing without letup," according to the scientists. It is another statement from the scientific community that global climate change is real and that the Earth is getting hotter. The authors of this particular paper are among those who attribute the current global climate change to human causes, primarily the production of greenhouse gases, notably carbon dioxide created by the burning of fossil fuels.

Now for the caveats. This particular paper was produced by three scientists from the Goddard Institute for Space Studies. It has been submitted to a scientific journal, Reviews of Geophysics, but it has not yet been accepted after peer review. Its findings must be considered in that light.

The lead author, James Hansen, is one of the most famous and most vocal advocates of the thesis of human-caused global warming. Just so you know.

Nevertheless, we take this as additional evidence that global warming is real and that we Americans, among others, ignore it at our peril. We would hope that the climate-change deniers in the Utah Legislature might take note.

Interestingly, the three authors comment in the summary portion of their paper on the political difficulties of the climate-change debate. They mention that climate-change reporting has become politicized, "a perhaps inevitable consequence of the economic and social implications of efforts required to alter the course of human-made climate change." Now there's a wonderful example of understatement.

The other reason that people may doubt global warming, the authors say, is that lay people's perceptions are strongly influenced by the latest fluctuations in the weather. That is happening today. Much of the United States had abnormally cool weather last summer (remember Utah's cold, rainy June) and both the United States and Europe had a cold winter (late December in Utah was particularly raw).

But weather is short-term. Climate is long-term. And Earth's climate, as a whole, is getting hotter.