The debate over anthropogenic global warming—a theory propounded by the UN IPCC—is often portrayed as an argument between deniers and true believers. The deniers supposedly claim that there is no global warming, man made or otherwise, and that the whole theory is a plot by left-wing agitators and closet socialists bent on world domination. The true believers, conversely, accept every claim of pending future disaster uttered by scientists and activists alike. As with most controversies both extreme positions are wrong and the truth lies somewhere in-between. As a scientist, I have studied the evidence and find the case for imminent, dangerous, human caused global warming unconvincing—here is why I am an AGW skeptic.

Forests and their soils are one of our planet's major sinks of biologically active carbon and contain the majority of Earth’s terrestrial carbon stock. Some climate change alarmists have said that the world's forest are in danger from the effects of climate change. Recent studies have shown increases in plant growth across many forest types. Now, a new paper in the Proceedings of the National Academy of Sciences reports that the increase in forest biomass is due to rising CO₂ levels and warmer weather—in other words, trees love global warming whether human caused or natural.

A 2009 editorial in the journal Nature Geoscience, opined that, if participants at the Copenhagen Climate Conference failed to map out a path for future greenhouse-gas emissions that is both effective and feasible, then humanity might have to consider turning to “geoengineering.” Geoengineering, a term unfamiliar to most, is the deliberate manipulation of Earth's climate system to control global warming. Since Copenhagen was a resounding flop, new geoengineering proposals have been springing up in a number of scientific journals. Science is still struggling to understand how climate works and what accidental impacts human activities have on that system. Now a number of “visionaries” want to mess with the planet on purpose—what could possibly go wrong with that?

A new report in Science underscores what many scientists have been saying for years, it's water vapor, not CO₂, that has been driving global temperature changes in recent decades. Stratospheric water vapor concentrations decreased by about 10% after the year 2000, slowing the rate of global surface temperature increase over the past 10 years. It also seems likely that water vapor in the stratosphere increased between 1980 and 2000, causing surface temperatures to warm by an extra 30% during the 1990s. These findings show that stratospheric water vapor represents an important driver of decadal global surface climate change, yet the IPCC crowd continues to focus on CO₂.

With all the predictions of short term climate catastrophes proffered by global warming alarmists it is hard to look forward to a future time on Earth. What does the future hold a thousand, ten thousand, a million years from now? Science has some predictions about that as well, though the news media have not picked up on them. What environmental changes await us on the long road ahead?

One well accepted definition of the “Three Pillars of Science” lists the three as theory, experimentation and computation. For climate science this translates into climate theory, gathering climate data, and climate modeling. The three pillars are due an update in this post Copenhagen, post Climategate world. After reviewing the past year's crop of discoveries and disclosures, it seems that all three pillars are still wobbly at best—even without questionable conduct on the part of warm-mongering researchers.

There have been a number of strange theories regarding the conditions deep within Earth's interior circulating around the internet. Claims that solar flares will cause nuclear reactions deep below our feet are perhaps the most ludicrous, but fairly easy to dismiss. More timely, perhaps, is the sudden conversion of global warming guru Al Gore into a geothermal energy booster. Evidently Gore thinks it's bad to drill for oil, but good to drill for heat. TV documentaries threaten mega-volcano eruptions and talk about mantle plumes underneath Hawaii, but just what does science tell us about our planet's interior?

A number of recent papers analyzing the nature of climate models have yielded a stunning result little known outside of mathematical circles—climate models like the ones relied on by the IPCC contain “irreducible imprecision.” According to one researcher, all interesting solutions for atmospheric and oceanic simulation (AOS) models are chaotic, hence almost certainly structurally unstable. Further more, this instability is an intrinsic mathematical property of the models which can not be eliminated. Analysis suggests that models should only be used to study processes and phenomena, not for precise comparisons with nature.

In an essay adapted from his 2009 AAAS Annual Meeting keynote address, James J. McCarthy has produced a fairly concise statement of the anthropogenic global warming believer's world view. After a self-serving review of climate science history, McCarthy trots out the usual litany of climate change troubles: increased cyclones, rain and floods, rising sea levels and, of course, those pesky tipping points. The tone of the article is set early on, when research is cited stating that mankind's impact on Earth is “sufficiently profound to declare that we have transitioned from the Holocene era of Earth history to the Anthropocene.”

There is another contender in the alternate energy, renewable fuels sweepstakes that combines aspects of solar energy and biofuels. Most solar technologies are aimed at producing electricity, but a new class of solar chemical reactors aims to make liquid fuels from air, water, and sunshine. This could, in theory, provide a carbon neutral replacement for liquid fossil fuels. The catch? The process is costly and unlikely ever to compete with gasoline produced from fossil fuels without a punishing tax on carbon emissions.

While climate skeptics have gleefully pointed to the past decade's lack of temperature rise as proof that global warming is not happening as predicted, climate change activists have claimed that this is just “cherry picking” the data. They point to their complex and error prone general circulation models that, after significant re-factoring, are now predicting a stretch of stable temperatures followed by a resurgent global warming onslaught. In a recent paper, a new type of model, based on a test for structural breaks in surface temperature time series, is used to investigate two common claims about global warming. This statistical model predicts no temperature rise until 2050 but the more interesting prediction is what happens between 2050 and 2100.

Twenty thousand years ago, North America had a more impressive array of big animals than Africa does today. The continent was populated by mastodon, several species of mammoth, giant ground sloths, saber-toothed cats and bison twice the size of their modern counterparts. By 10,000 years ago most of these animals were gone, including the 10 species that weighed more than a ton. Many drastic changes occurred during this interval, including the arrival of Homo sapiens to the new world. Many have cited humans as the cause of this great megafaunal die-off: were H. sapiens causing mass extinctions even during the stone age?

Recent claims by climate change alarmists have raised the possibility that terrestrial ecosystems and particularly the oceans have started loosing part of their ability to absorb a large proportion of man-made CO₂ emissions. This is an important claim, because currently only about 40% of anthropogenic emissions stay in the atmosphere, the rest is sequestered by a number of processes on land and sea. The warning that the oceans have reached their fill and their capacity to remove atmospheric CO₂ is accompanied by the prediction that this will cause greenhouse warming to accelerate in the future. A new study re-examines the available atmospheric CO₂ and emissions data and concludes that the portion of CO₂ absorbed by the oceans has remained constant since 1850.

Climate and environmental scientists have become dependent on computer models in recent decades. The scientific literature and the popular press are filled with strident warnings of impending natural disasters, all predicated on the output of computer programs. The IPCC has solemnly predicted that climate change will drive thousands of species to extinction if anthropogenic global warming is not reined in. The coprophagous press has uncritically swallowed these computer generated droppings, reporting conjecture as fact and possibilities as certainties. Even though the climate change faithful continue to blindly believe the IPCC predictions, at least some researchers are aware of the glaring flaws in their computer models.

There are a number of scientists who disbelive the theory that an asteroid impact killed the dinosaurs. They point to evidence that some species of sauropod may have survived the Chicxulub impact—widely hailed as the smoking gun in the dinosaur extinction—as proof that the event was simply not big enough to be a knockout blow. Now, according to Sankar Chatterjee of Texas Tech University, new information reinforces his claim that a much larger impact that he has named Shiva, actually did the dinosaurs in.