Mixed in with the swirling cloud of misinformation about global warming is also a bit of blather regarding the onset of a new Ice Age. What the promoters of a new big freeze are talking about is a glacial period, since technically we are still in the midst of an ice age—the Pleistocene. A number of scientists have warned that the planet might be headed for a new period of glacial growth based on Earth's recent history. Over the past half million or so years there has been a series of short (15-20k year) warm period sandwiched between longer (70-100k year) glacial episodes. Make no mistake, global cooling is much worse than global warming, so this really matters to our descendants and the whole human race. Now, a new study in Nature says that we maybe off the hook, glacial wise. Not only that, human activity might be the reason.
A lot has been written about melting ice caps and new mini-ice ages recently. Seems that science can't decide if we are going to drown in rising oceans or starve because summer will be a thing of the past. This leaves the layperson justifiably confused as to who to believe—the climate change alarmists who back rapid global warming or those who warn of a new glacial period. There is little certainty when it comes to science but one thing that can be counted on is our ignorance. Quite simply, scientists cannot predict with any certainty what Earth's climate will do next. If someone tries to tell you different they are lying.
A study of ancient volcanic ash found at key archaeological sites across Europe suggests that early modern humans were more resilient to climate change and natural disasters than commonly thought. The study, which appeared in PNAS, analyzed volcanic ash from a major eruption that occurred in Europe around 40,000 years ago. The volcano spewed so much ash that the event probably created winter-like conditions and a sudden colder shift in climate. Scientists have generally suggested that the spread of modern humans, and the decline of our cousins the Neanderthals, was primarily due to ancient volcanic eruptions and deteriorating climate conditions, but this study shows that stone-age man rolled with the punches and shrugged off the sudden shifts in climate. This new evidence flies in the face of modern predictions that a shift of a few degrees in average yearly temperature will decimate human populations world wide.
Another group of researchers has weighed in on the continuing scientific scuffle over whether the Himalayan glaciers are melting. A letter to Nature Geoscience reports that the Karakoram glaciers, a part of the greater Himalaya north of the actual Himalaya Range, are actually gaining mass. Outside the ice sheets in Greenland and Antarctica, the Karakoram is the most heavily glaciated part of the world, containing nearly 3% of the planet's total ice area. But because they are so large, difficult to get to and dangerous to travel on, they have not been measured by conventional survey methods. Scientists have instead, been relying on satellite measurements, whose accuracy is now called into question. This impressive new study says that the Karakoram glaciers are not only not shrinking, they are accumulating enough ice each year to cause a slight decrease in ocean sea-level.
A new study in the Proceedings of the National Academy of Sciences (Early Edition on-line), is shaking up science's view of polar bear evolution. Previously, it had been suggested that the white bear of the north was a relatively young species that diverged from brown bears during the last glacial period. That glaciation started after the Eemian epoch (~125,000 years ago), peaking around 25,000 years ago. New genetic analysis pushes that estimated divergence back to 4-5 million years ago, though there seems to have been a significant level of interbreeding between the two species over time. Another important finding is that the polar bear population underwent a significant contraction around 500,000 years ago. According to this new information the polar bear has been around for much longer than previously thought, implying that it has survived many interglacial warm periods. In other words, those who think the polar bear cannot survive the shrinking of Arctic ice packs are dead wrong.
You know, in science, there was once this thing we called the Theory of Multiple Working Hypotheses. Anathema (a formal ecclesiastical curse accompanied by excommunication) in modern climate science. So, in juxtaposition to the hypothesis of future global climate disruption from CO2, a scientist might well consider an antithesis or two in order to maintain ones objectivity. One such antithesis, which happens to be a long running debate in paleoclimate science, concerns the end Holocene. Or just how long the present interglacial will last.
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.
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.