The current interglacial warm period, the Holocene, started ∼11,500 years ago. At its start, among the dramatic changes in climate was a notable increase in rainfall, triggered by summer insolation values higher than those of today. This caused what is called the African Humid Period in North Africa—a time when the Sahara was dotted with large and small lakes, savannah grasslands, and in some regions, humid tropical forests and shrubs. The African Humid Period ended abruptly ∼5000 ybp (years before present) in many locations, such as western North Africa and northern Kenya. In other places, such as the central Sahara and the southern Arabian Peninsula, change occurred more gradually, taking several millennia. Regardless of the pace of change, those areas are tracts of arid desert today, and the animals and humans who had previously thrived in those formerly verdant regions have either moved or had to adapt to much harsher conditions. This is but one example of nature at its most capricious—the tyranny of climate change.
Climate alarmists are constantly warning that Earth is going to warm up, driven they say by the level of CO2 in the atmosphere. To bolster their claims they point to the Pliocene, a time 4-5 million years ago, when the planet was 4-8°C hotter and CO2 levels were 400ppm or higher. This is the climate we are heading for, the global warming supporters say—but it that really true? Superficially it seems a plausible assertion, but as it turns out there is much more here than CO2 and temperature. It is not just the average temperature but the distribution of temperature at different latitudes, both over land and sea, that controls the climate. It is the temperature gradient that drives storms and affects weather patterns and it was much different during the Pliocene. Moreover, climate models do not generate a Pliocene like climate when run with higher CO2 levels, which means climate scientists are missing something important about the way Earth's climate system works.
It has been vilified in the press and maligned in school classrooms by the ignorant. Opposing it has become a cause célèbre in Hollywood an a litmus test for liberal politicians. Labeled man's chosen weapon for ravaging nature and laying waste to the environment this poor, largely misunderstood gas is in fact essential to our existence. Without carbon dioxide, CO2, we would not be here and Earth would be a frozen lifeless chunk of rock. Forget that life would never have developed on a planet without greenhouse warming, a recent scientific study say the daemon gas has rescued the planet from the deep freeze at least twice during the Neoproterozoic era, roughly 750 to 635 million years ago.
Recent days have seen a number of announcements about our changing climate. As it turns out Arctic ice is rebounding, sea levels are dropping and things just are not going according to the IPCC's plan for catastrophic global warming. Faced with reversal after reversal, it might seem logical for mainstream climate scientists to admit that they are wrong, that global warming is not taking place at a breakneck pace, but this has not happened. Instead, climate change apologists are weaving a tangled web of excuses—hot is cold, wet is dry, up is down. No matter what happens to the world we live in, the root cause according to the doomsayers is always the same: it's always global warming's fault.
Most people fall into one of two categories when it comes to predictions of future climate calamities: they either do not realize that the predictions are predicated on computer models or they unquestionably trust the models to reveal the future. A clear and lucid online article in Nature Geoscience addresses the current state and limitations of climate modeling. The article points out that State-of-the-art climate models are largely untested against actual occurrences of abrupt change. “It is a huge leap of faith to assume that simulations of the coming century with these models will provide reliable warning of sudden, catastrophic events,” the author states. To counter claims of predicted “tipping points,” incidents of abrupt climate change from the past are examined—incidents that current models get wrong.
Recently, the 3rd Nobel Laureate Symposium decided to hold a trial, charging humanity with ruining the planet. Based on the so called 9 Planetary Boundaries, a jury of 20 Nobel Laureates sat in judgment while “compelling evidence” was presented showing that “humanity may now be capable of radically altering the remarkable conditions for life on Earth.” The Planetary Boundaries approach was developed by 28 scientists, who estimated that three of the boundaries, climate change, the nitrogen cycle and biodiversity loss, have already been crossed and that several others are all ready in dangerous territory. We have all been charged with transgressing boundaries laid down by a group of scientists most people have never heard of, judged and found guilty by a gaggle of Nobel Prize winners, and been remanded to the UN for punishment. This sham trial does not represent justice but an attempt to place humanity in ecological bondage.
There has been a resurgence of alarmist claims regarding the pending extinction of a majority of Earth's lifeforms due to human misdeeds—clearing rain forests, polluting the oceans and, of course, causing global warming. Perennial crank and misanthrope E. O. Wilson leads the parade of doomsayers, claiming that biodiversity is dropping and a sixth major extinction event is just around the corner. What evidence backs these claims? Why, computer model projections, naturally. The facts are researchers have identified 1.4 million animal species so far, and recently a pair of Brazilian researchers estimated that there are estimated 5.4 million yet-to-be-discovered animal species alone. The truth is, scientists have no idea how fast biodiversity is falling because they have no idea how many species there are on Earth. And the researchers put a price tag on finding out that is simply stunning.
Fluctuations in surface melting are known to affect the speed of glaciers and ice sheets, while the contribution of glaciers and ice caps to global sea-level rise is uncertain at best. Much has been made of the “accelerating” loss of ice from the Greenland glaciers. Over the past decade, Arctic sea ice retreated substantially during the summer months, and some predicted that the ice loss could be irreversible, a tipping point that would boost global warming. A number of new papers in Nature, Geophysical Research Letters and Nature Geoscience, shed new light on these subjects, and the answers are not the ones usually heard in the media.
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.
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.”
Two articles in the July 17 edition of Science describe efforts to model Earth's rapidly changing climate at the end of the last glacial period, between 21 and 11 thousand years years ago (ka). After a year and a half of number crunching on Oak Ridge National Laboratory's Jaguar supercomputer, the first results indicate that climate experienced cooling 17 ka, during the Heinrich Event 1 (H1), followed by an abrupt warming at the onset of the Bølling-Allerød Warming 14.5 ka. These abrupt climate changes were accompanied by large changes in the “ocean conveyor belt”: the Atlantic meridional overturning circulation (AMOC). The results suggest that this transition can be viewed simply as the North Atlantic climate response to rapidly changing glacial meltwater flow. The findings call for a paradigm shift in our understanding of abrupt climate change and weakens the threat of “irreversible tipping points” so popular with climate change extremists.
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?