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.
The current hot phrase bandied about by talking heads and parotted by news pundits is “tipping point.” We are told that the climate may be near a tipping point, if it has not crossed one already, and that can't be good. But what is a tipping point, where do they come from and how can we identify one when we see it?