Instrument data from the last 160 years indicate a general warming trend during that span of time. However, when this period is examined in the light of palaeoclimate reconstructions, the recent warming appears to be a part of more systematic fluctuations. Specifically, it is an expected warming period following the 200-year “Little Ice Age” cold period. Moreover, a new study of the natural variability of past climate, as seen from available proxy information, finds a synthesis between the Milankovitch cycles and Hurst–Kolmogorov (HK) stochastic dynamics—a result that shows multi-scale climate fluctuations cannot be described adequately by classical statistics.
Given the ongoing controversy over global warming the question of whether humans can change Earth's climate is a familiar one. Lost in the fight over anthropogenic global warming is a more subtle and possibly more important question—how has climate changed people. In recent decades, the fossil record of hominin evolution and behavior, though still incomplete, has improved greatly. Triggered by a recent National Research Council (NRC) report, a perspective article in the journal Science poses the question, “did climate change shape human evolution?”
Climate alarmists have been slow to learn that their over-reliance on computer models and unproven theories has harmed their public credibility. In an attempt to counter the richly deserved bad press that climate science has been garnering these days, a number of global warming true believers are trying a different, more fact based approach to scaring the public. One such attempt recently appeared in the journal Science—not as a paper describing original research but as a perspective article. In it, a Senior Scientist at the National Center for Atmospheric Research, in Boulder, Colorado, attempts to “weave together” some carefully selected “threads in the discussion of climate” to arrive at a very familiar and unconvincing conclusion.
Much has be written and even more said about stopping climate change. The total foolishness of such a quest is obvious to anyone with even the most cursory understanding of Earth's climate over the Past 65 million years. The more science learns about the ever changing nature of climate the more capricious nature appears and the less significant the labors of H. sapiens are revealed to be. To place the ludicrous arguments and unsubstantiated fears of climate catastrophists in perspective, it is instructive to survey Earth's climate since the demise of the dinosaurs—the geological time period called the Cenozoic Era. During this long span of time, Earth's climate has undergone a significant and complex evolution. If one truth has been discovered by human science it is that Earth's climate is always changing, driven, as one set of researchers put it, by trends, rhythms and aberrations—the mechanisms of climate change.
A new paper, penned by a group of known warmist scare mongers, claims to have proof that CO2 is the control knob that regulates Earth’s temperature. Andrew A. Lacis, Gavin A. Schmidt, David Rind, and Reto A. Ruedy, all from NASA's Goddard Institute for Space Studies, are boasting they have experimental proof that “carbon dioxide is the single most important climate-relevant greenhouse gas in Earth’s atmosphere.” Even though this climate alarmist cabal admits that H2O, in the form of water vapor and clouds, accounts for 75% of greenhouse warming, they still claim that that CO2 is king. Why? Because water's contributions are supposedly caused by feedbacks involving carbon dioxide. How have they proven that? By fiddling around with the same biased computer climate models that their other fictitious claims are based on.
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.
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.
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?
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.”
A new study has confirmed the astronomical theory of the ice ages, but with a new twist: The shutoff of the meridional ocean circulation, or MOC, and an associated southward shift of tropical monsoon rain belts seems to play an integral role in the melting of glacial period ice sheets. These changes cause warming of the Southern Hemisphere and a rise in atmospheric CO2 levels, which in turn provides a positive feedback loop that helps drive glacial termination. This is why, every 100,000 years or so, the great Northern Hemisphere ice sheets collapse and glacial conditions give way to a warm interglacial period, such as the Holocene warming humanity is currently enjoying. This, however, does not support recent claims that global warming is causing the Southeast Asian monsoon to fail.
While the IPCC and global warming alarmists continue to claim climate change is controlled by atmospheric CO2 levels, most knowledgeable scientists will tell you that climate change is caused by variation in Earth's orbit and orientation. These periodic changes in movement and attitude are called the Milankovitch Cycles. A new paper, to be published in Science, confirms that glacial terminations are caused by Earth's orbital cycles, not carbon dioxide.
Increased insolation 20,000 years ago caused deglaciation in the Northern Hemisphere, according to a new report in the August 7, 2009, edition of Science. Further more, it was the onset of deglaciation of the West Antarctic Ice Sheet, which occurred between 14 - 15 thousand years ago, that was the source of sea-level rise at the beginning of the Holocene warming. Such events are often associated with rising CO2 levels by climate catastrophists but the evidence says otherwise.
Having reported that scientists did not find CO2 responsible for a change in the duration of ice age glacial periods 700,00 years ago, another new report takes a look at the conditions around the last interglacial warm period and our own Holocene warming. Using corals from the south seas paradise of Tahiti to track sea-level changes, researchers probed the mechanisms driving Earth's climate between glacial and interglacial states. Almost as an after thought they added that there is no longer any doubt: changes in sea-level drive changes in CO2, not the other way around.
Around 1.2 million years ago, a shift in global climate began that caused a change in the timing of the alternating warm and cold periods—called interglacials and glacials—that have persisted during the Pleistocene Ice Age. Prior to that time, ice age glacial periods lasted about 40,000 years but since ~700,000 years ago ice-age cycles have lasted for around 100,000 years. Orbital variations, called the Croll-Milankovitch cycles, do exert some forcing on the 100,000 year time scale, but it is relatively weak. Orbital cycles seem to many too feeble an explanation for the change in glacial-interglacial timing. Some scientists have attempted to attribute the timing shift to a drop in CO2 but a new study confirms that carbon dioxide levels were not the cause of the climate shift.