The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) projected that global sea level will rise by up to 60 cm by 2100 due to global warming. The cause of this rise is twofold: expansion of ocean waters as they warm and additional water from glaciers melting. Despite nearly stable sea levels over the past 3,000 years, a number of low-lying and island nations have seized on the imminent flood as a reason to demand reparations from developed nations. In reality, most of the areas in the world that are suffering from inundation are threatened because of human actions, but not global warming. Damming and rerouting of rivers combined with over-pumping of ground water has led to subsidence in many areas—in other words, the seas are not rising, the land is sinking.
According to a recent paper, human actions may have caused Earth's climate to warm much earlier than previously expected. In an article to be published in Geophysical Research Letters, and widely reported in the media, around 15,000 years ago, early hunters were a major factor in driving mammoths to extinction. Supposedly, this die-off had the side effect of heating up the planet. This is an interesting conjecture, since a letter just published in Nature Geocience reaches the opposite conclusion regarding climate and the mammoths' decline. This mammoth confusion illustrates the uncertain and even contradictory evidence that abounds in climate science.
After nearly 50 years of acceptance, the theory that a great ocean “conveyor belt” continuously circulates water around the globe in an orderly fashion has been dismissed by a leading oceanographer. According to a review article in the journal Science, a number of studies conducted over the past few years have challenged this paradigm. Oceanographers have discovered the vital role of ocean eddy currents and the wind in establishing the structure and variability of the ocean’s overturning. In light of these new discoveries, the demise of the conveyor belt model has been become the new majority opinion among the world's oceanographers. According to M. Susan Lozier, of Duke University, “the conveyor-belt model no longer serves the community well.”
Around 3 million years ago, Earth's climate started growing colder. Glaciers began forming in high northern latitudes, while surface waters cooled in parts of the equatorial Atlantic and Pacific Oceans. At the same time, climate sensitivity to variation in the tilt of Earth's axis—called obliquity—increased substantially. Since that time, changes in sunlight associated with obliquity have caused variation in global ice volume and equatorial sea surface temperatures (SST). Inexplicably, variations at the equator occurred a few thousand years before those in high latitudes and thus could not have been a direct consequence of the waxing and waning of glaciers. Two new papers in the June 18, 2010, issue of Science attempt to explain the true causes of climate change.
In the midst of the clamor over global warming, greenhouse gas emissions and world energy supplies another, perhaps more immediate, environmental catastrophe is gathering momentum—the world wide shortage of fresh water. Though eclipsed in America by pictures of oil-soaked pelicans and fouled coastal wetlands, this potentially more disastrous and more permanent problem has been ignored by politicians and the public for decades. Experts are warning that by 2050 fully 45% of humanity may be chronically short of water. Unlike the eventual depletion of the world's oil supplies, there is no substitute for H2O.
Since the Mid-Brunhes Event, around 430,000 years ago, interglacial periods have grown warmer and their CO2 levels higher. Research confirms that Croll and Milankovitch were right: Earth's orbital cycles seem to be the cause of these documented cases of true global warming, with CO2 playing a supporting role, not the lead. Many of the catastrophic events warned of by climate change alarmists turn out to be well within the range of natural variation. Moreover, new findings indicate that the effects of the cycle induced changes, through their impact on the environment in the Southern Hemisphere, are not correctly accounted for in the IPCC models.
March 20, the Eyjafjallajökull volcano began erupting after slumbering for almost 190 years. The eruption also brought a threat of floods and earthquakes, while the resulting plume of volcanic ash shutdown the European airline industry, costing an estimated $200 million a day. In the short-term, the volcano has been bad for Northern Europe and given a boost to Iceland's tourist industry, but there are larger questions involved. With tedious predictability, a number of climate change alarmists quickly claimed that the volcano was caused by global warming. A more likely outcome is a cool Northern Hemisphere summer caused by airborne ash—which could give the alarmists an excuse for the continued lack of global temperature rise.
Recently, a number of papers have surfaced that use advanced statistical methods to analyze climate data. The techniques involved have been developed not by climate scientists but by economists and social scientists. These new tools belong to the field of econometrics. The use of statistical break tests and polynomial cointegration to analyze the relationships between time series data for greenhouse gas concentrations, insolation, aerosol levels and temperature have shown that these data are non-stationary. The implication of these findings is that much of the statistical analysis applied by climate scientists is flawed and potentially misleading. So strong is the statistical evidence that a couple of economists are claiming to have refuted the theory of anthropogenic global warming. This, on top of everything else that has recently transpired, may indicate that a climate change paradigm shift is imminent.
Earth's climate history includes numerous incidents of rapid warming and cooling. While Pleistocene ice-age glacial terminations are arguably the most dramatic recent examples of sudden climate change, during the last glacial period the climate of the Northern Hemisphere experienced several other significant episodes when the climate rapidly warmed. Scientists call these episodes Dansgaard-Oeschger (DO) events after the Danish and Swiss researchers who documented them using ice-core studies. These rapid oscillations are marked by rapid warming, followed by slower cooling. The most prominent coolings are associated with massive iceberg discharge into the North Atlantic Ocean known as Heinrich events (HE). The melting icebergs add large volumes of cold fresh water to the ocean, disrupting circulation patterns and causing further climate changes. Scientists look to past events like these to help us understand how Earth's climate system functions—what causes our planet to cool or suddenly warm. Recently, new data on past climate changes have led one commentator to predict the end of winter skiing in the American Southwest.
There have been a rash of bogus reports in the news media about rapidly rising sea-levels supposedly caused by global warming. Sea-levels are notoriously hard to measure on a global basis since land also rises and sinks due to tectonic activity. With historical records mostly unreliable how can we tell if current conditions are normal for Earth 14,000 years after a deglaciation? A new report, based on calcium growths in caves on the Mediterranean island of Mallorca, says that sea levels around 81,000 years ago were higher than today. Higher sea-levels imply less glacial ice and warmer temperatures than today as well. Even more interesting is that this occurred during a warm period called marine isotope stage (MIS) 5a, which was more than 30,000 years after the Eemian interglacial ended and glaciation had resumed. This could mean that current theories about how ice age glacial periods start are wrong.
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.
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?
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.”
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?