The electric car, seemingly on its death bed throughout the 90s and much of this decade, appears over the past two years to be rising from the grave. Every car company worth its road salt is rushing to put a plug-in hybrid or an all-electric car on the market.

All-electric cars directly release no air emissions, and they seem for many a perfect green alternative to “clunkers,” SUVs, and other road hogs dependent for their get-up-n’go on internal combustion engines.

Cars of course need energy to move, so when someone plugs in an electric car, the battery is charged with electricity from the electric grid. In the U.S., electricity generation is responsible for about 40 percent of total carbon emissions. So from a full life-cycle standpoint, electric cars are hardly zero-emissions when it comes to carbon; and depending on where one lives, a new electric car may not be the only - or the optimum - choice, at least until we get more renewable energy on our grid.

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Global temperatures have seemingly plateaued in the past 10 years. Those dubious about climate science or wary of the social implications of carbon regulations have seized on this point to argue that fears of global warming have been overblown.

However, a careful analysis of the data reveals that this decade has in fact been anomalously warm - the warmest in the history of recorded global temperatures by a fair margin - and the rate of warming is consistent with that over the prior few decades. The real question at hand is not whether warming is occurring, but rather whether the rate of warming is faster or slower than expected by climate scientists.

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Scientists are increasingly finding that black carbon aerosols in the atmosphere and their deposition on snow and ice-covered areas are having more of a warming effect than earlier thought.

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Human emissions of carbon dioxide (CO2) are the primary factor contributing to the warming of the Earth’s surface over the past half-century.

However, for the past few years global temperatures have been stagnant or slightly decreasing even as atmospheric CO2 concentrations have been increasing faster than ever. This situation has led some voices in the media and blogging world to challenge the relationship between the CO2 concentrations and warming. These critiques are flawed, however, as short-term changes in global temperature are driven by numerous factors going beyond CO2, and the recent disconnect between the two is not particularly unusual in light of their past relationship.

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The recent brouhaha (see related story, this posting) initiated by conservative columnist George Will’s February 15th syndicated column centers in part around his assertion that global sea ice levels now equal those of 1979, belying concerns of melting ice caps.

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In reporting on climate change, the carbon, carbon dioxide (CO₂), greenhouse gases, radiative forcing, and CO₂-equivilent (CO₂-eq) are often used almost interchangeably to refer to the human contribution to recent warming.

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It is difficult these days to find an article about climate science without some mention of tipping points and the risk of abrupt climate change.

Some prominent climate scientists and policy proponents have warned ominously that we have only a decade left to change our ways to “avert catastrophe.” The clock is running.

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With all the attention surrounding carbon dioxide these days, it is easy to forget that there are a number of other important natural and human-driven factors (”forcings” in climate circles) that influence Earth’s climate.

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An argument frequently used by those skeptical of the role of anthropogenic greenhouse gases in modern temperature increases is that warming is caused by the Sun.

At first glance, it seems to make intuitive sense: the Sun is a massive nuclear fusion reactor a million times larger than Earth, it is responsible for almost all the energy reaching our plant, and in the past few decades scientists have learned that solar activity varies significantly over time. Surely it must have a larger impact on our changing climate than a gas that comprises only a small fraction of our atmosphere?

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Measuring Earth’s temperature is no easy task.

Four different groups produce temperature records that attempt to compile a single global mean surface temperature: NASA’s GISStemp, the Hadley Center’s HadCRU, Remote Sensing Systems’ RSS, and the University of Alabama, Huntsville’s UAH.

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