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?”
For decades, climate change alarmists have generated a host of doomsday scenarios, all based on the theory of anthropogenic global warming: human CO2 emissions will force Earth's climate to warm uncontrollably causing all manner of unpleasantness. A new study, published by the Center for the Study of Carbon Dioxide and Global Change, addresses the major predicted effects of global warming head on. Making extensive use of peer reviewed research papers, the dire predictions of climate alarmists are demolished point by point. In fact, the authors conclude that rising atmospheric CO2 concentrations associated with the development of the Industrial Revolution have actually been good for the planet.
Around 19,000 years ago, oceanic conditions underwent dramatic changes that coincided with a shift in global climate, marking the onset of the Holocene warming. In the North Atlantic, major changes in the Meridional Overturning Circulation (MOC), which carries warm and highly saline surface water north to cooler regions, played a substantial role in regulating climate and levels of atmospheric carbon dioxide. Scientists are now convinced that the ocean absorbed, stored, and released vast quantities of carbon in the past, playing a major role in the end of the last Pleistocene Ice Age glacial period. Understanding the ocean's role in the past is important to understanding how it may influence climate in the future. A new report in Science shows that the MOC experienced a series of abrupt changes that lasted from decades to centuries, and may have stored and released more CO2 than previously thought.
With massive floods in Australia and Brazil, and bitter winter weather across the Northern Hemisphere, climate change alarmists have been quick to blame the severe weather on global warming. The fact that such weather is well within normal variation has not stopped the catastrophists from claiming vindication. No matter that those who study the Pacific and Atlantic decadal scale oscillations predicted a cold and snowy winter for Europe and North America, the recent blizzards are being offered up as “proof” that Earth's climate is changing for the worse. And what of the reports of widespread natural disaster from Rio, Brisbane and elsewhere? Even more global warming, of course. When it comes to wicked weather, the climate change cabal's misinformation machine is running at full tilt.
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.
Time after time, the public has been harangued by climate change “experts” predicting all form of devastation due to anthropogenic global warming. The Greenland and Antarctic glaciers will melt, as will the sea ice covering the Arctic Ocean. Temperatures will rise by 2-6°C, perhaps more in higher latitudes. Weather patterns will shift, there will be droughts and torrential monsoon rains, cyclones will increase in intensity—where will it all end? Here's a thought, we might find the world a nicer place after a bit of global warming. In fact, given the general cooling trend seen over the Holocene (the period since the last glacial period ended around 14,000 years ago) and the Cenozoic (the time since the dinosaurs died, around 65 million years ago) human CO2 may be, in some small way, the only thing delaying another devastating ice age.
Carbon monoxide, CO, is a trace gas that is important in atmospheric chemistry. It indirectly influences climate and has significant effects on methane and ozone levels. CO is a byproduct of combustion—particularly the incomplete burning of fossil fuels and biomass—and conventional wisdom says that humans, with their tendency to set things on fire, should be responsible for releasing much of the gas into the atmosphere. Little is known about the abundance and sources of CO prior to the industrial age, or about the importance of anthropogenic activities have had. A new study in the journal Science presents a 650-year-long record of CO atmospheric concentration using samples from Antarctic ice cores. Reconstructed past CO variability and its causes have come up with a shocking fact: CO levels are at a 2,000 year low. Apparently, humans actually prevent wildfire, reducing the release of carbon monoxide and, consequently, CO2.
The influence of the Sun on Earth’s climate over time scales of centuries and millennia is all but ignored by current climate change dogma, with many climate scientists dismissing solar variation as too feeble to have much of an impact. Though it was recently discovered that variation at ultraviolet wavelengths is considerably greater than at lower frequencies, the change in total solar irradiance over recent 11-year sunspot cycles amounts to <0.1%. New research on longer time scales finds the change in total irradiance sufficient to affect the dynamics of the El Niño–Southern Oscillation (ENSO). Detailed model studies of the Little Ice Age (~1400 to 1850 AD) conclude that the Sun controls an “ocean dynamical thermostat” that affects climate variability over large regions of the globe. It was also found that fully coupled general circulation models (GCMs), the kind used by the IPCC to make predictions of future global warming, lack a robust thermostat response. This means that the sensitivity of the climate system to solar forcing is underestimated by current GCMs—the climate models are proven wrong again.
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.
Though Earth and its climate are billions of years old, climate science is still very young. So young that surprising new discoveries are constantly being made. One such discovery in the field of paleoclimatology—the study of Earth's climate in the distant past—was the uncovering of a period of great warming around 40 million years ago, in the middle of the Eocene Epoch. In the midst of a general cooling trend beginning at the end of the preceding Paleocene Epoch (~55 mya) there were a number of dramatic, sudden bursts of global warming. The most celebrate of these is the Paleocene-Eocene Thermal Maximum or PETM, when surface temperatures rose by 5-7°C. Recently, science has discovered another hot interval 15 million years later during the Middle Eocene. Named the Middle Eocene Climatic Optimum (MECO), it marked a time when deep sea temperatures rose about 4-5°C and atmospheric CO2 levels peaked. As new information is uncovered, climate scientists are scrambling to interpret what caused this second, more sustained period of warming and what it may mean for current climate conditions.
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.
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.
Asking the somewhat obvious question, “are cold winters in Europe associated with low solar activity?” a group of scientists have announced that the answer is yes. While this may seem unsurprising, the finding is another indication that Earth's climate is not simply driven by greenhouse gas emissions. Even so, some scientists are only grudgingly accepting the finding, cautioning that this only applies in the central UK and refusing to admit that the Sun could affect global mean temperatures as well. Still, the researchers found that average solar activity has declined rapidly since 1985 and cosmogenic isotopes suggest a possible return to Maunder minimum conditions within the next 50 years. This could be a sign that climate science is starting to recover from its CO2 fixation.