Once again climate scientists have put forth a scary prediction about melting ice caps and once again they are portraying output from computer models as a reliable prediction of things to come. The normally staid and reliable journal Nature emblazoned its cover with “Rising tide” in large black print, with the subtext “A 500-year model of Antarctica's contribution to future sea-level rise” in smaller print below. When a closer look is taken at this new model it turns out to be a house of cards, incomplete and built on top of other climate change models that are known to be faulty. As the old saying goes: garbage in, garbage out. Yet a major science journal chose this piece of computerized legerdemain as its lead article. No wonder that climate alarmists, and climate science in general, have fallen into such ill repute.
In the year 536 AD the sun dimmed, and the gloom lasted for more than an entire year. There were frosts and snows in the middle of summer and observers reported that winter never really ended. The sudden shift in climate lead to famine, plague and the fall of empires. What was worse, that year was only the beginning of a shift in climate that brought misery to the entire Northern Hemisphere for more than a century. Yet this well documented period of global cooling was smoothed away by climate change alarmists in works of fabricated data like the infamous “hockey stick” tree ring history. A new analysis has rediscovered this dark period in recent human history, fittingly made possible by new tree-ring measurements from the Altai mountains in Russia. The results help complete a climatological history stretching back 2,500 years. Climate history is a pesky thing, it just won't go away and can't be changed to fit some scientists pet theories.
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.
We have all heard about the Ice Age, if only in cartoon movies. A time when massive ice sheets covered the planet while mammoths and saber toothed cats roamed the frozen landscape. What is more, the cycle of interglacial-glacial-interglacial has happened over and over again during the past million or so years. During the last half a million years the cycle has repeated every 130,000 years, with the warm period we are now enjoying—the Holocene—just the latest interglacial respite from the icy conditions of the Pleistocene Ice Age. What most people don't know is that there were many areas on Earth that remained unchanged, even during the height of the last glacial period. The Sahara was hot and dry, and in the Amazon rainforests, though a bit smaller in area, looked much like they do today.
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.
Climate scientists have constructed models to predict what Earth's climate will look like decades, even hundreds of years in the future. Unfortunately, many major components of Earth's climate system have not been accurately monitored for very long. This makes such predictions suspect if not laughable. A case in point are variations in ocean circulation and temperature. In the Atlantic there is a cycle for sea surface temperatures variation called the Atlantic Multidecadal Oscillation (AMO). The AMO is linked with decadal scale climate fluctuations like European summer precipitation, rainfall in Europe and India, Atlantic hurricanes and variations in global temperatures. A new study in the journal Nature reports that the AMO is again transitioning to a negative phase, meaning the vaunted “pause” in global warming may be with us for decades. In fact, scientists at the University of Southampton predict that cooling in the Atlantic Ocean could cool global temperatures a half a degree Celsius.
As the new year begins the forces of climate alarmism find themselves in disarray. The world refuses to warm, despite contorted data manipulation aimed at squeezing out a claimed “hottest year ever” record by NOAA. One hundredth of a degree does not a warming trend create. Northern hemisphere temperatures are depressed for the second year in a row—also not a climate trend in itself but a psychological blow to the warmists trying to sell the idea that temperatures are at a record high. Moreover, there are indications that the climatologists' bane, CO2, is not ravaging tropical forests and is not being produced where the “blame the developed world first” crowd expected. In all, a good start to the new year because it is a bad start for the alarmists.
Marine and terrestrial proxy records suggest that there was a peak in global warming between 10,000 and 6,000 years ago, following the end of the last glacial period. Since the Holocene Thermal Maximum, Earth has undergone global cooling. The physical mechanism responsible for this global cooling has remained unknown and doesn't fit in with the current CO2 based climate models. Those climate models generate a robust global annual mean warming throughout the Holocene, mainly in response to rising CO2 levels and albedo changes due to retreating of ice sheets. In other words, the models disagree with reality, and when models disagree with nature the models have a credibility gap. A new paper in the Proceedings of the National Academy of Sciences (PNAS) says this model-data inconsistency indicates a critical reexamination of both proxy data and models is called for.
One of the greatest failures of climate science has been the dismal performance of general circulation models (GCM) to accurately predict Earth's future climate. For more than three decades huge predictive models, run on the biggest supercomputers available, have labored mighty and turned out garbage. Their most obvious failure was missing the now almost eighteen year “hiatus,” the pause in temperature rise that has confounded climate alarmists and serious scientists alike. So poor has been the models' performance that some climate scientists are calling for them to be torn down and built anew, this time using different principles. They want to adopt stochastic methods—so called Monte Carlo simulations based on probabilities and randomness—in place of today’s physics based models.
Forty million years ago, Earth began slipping from a “hothouse” climate to an “icehouse” climate. Currently the planet is in a brief warm interlude know as an interglacial—a period of retreating ice sheets and shrinking glaciers. As the word interglacial suggests, our current comfortable climate is not permanent, but merely a pause between frigid ice age conditions. Though climate alarmists and media talking heads continue to natter on about uncontrollable rising temperatures a more devastating climate change would be a descent into an ice age so cold and so deep that the entire globe freezes over—it has happened before. A new scientific paper reveals what researchers say is a feedback mechanism that acts as a natural thermostat and keeps Earth from cooling to the point of uninhabitability.
One of the scary scenarios frequently trotted out by climate change alarmists is the possible shutdown of the ocean currents in the Atlantic Ocean. This would disrupt northern hemisphere climate, particularly in Europe. Indeed, one Hollywood disaster movie had frozen military helicopters falling from the skies in the UK and Manhattan buried under a tsunami of ice. We are told this could happen at any time, if the world gets too hot from all that CO2 our species is churning out. Now a shocking new paper in the journal Science implies that the standard view of a relatively stable interglacial circulation may not hold for conditions warmer/fresher than at present. Why? Because it happened before, over 100,000 years ago, without the help of man made global warming. Another catastrophic climate threat is shown to be totally natural and to have happened before our species began burning coal and driving SUVs.
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.
Scientists have long suspected that the orbital cycles of our planet are responsible for the periodic climate variation that causes alternating glacial and interglacial periods. Milankovitch's theory of orbital cycles suggests that summer insolation at high northern latitudes drives the glacial cycles. Moreover, statistical analyses have demonstrated that the glacial cycles are indeed linked to eccentricity, obliquity and precession. Now, researchers have confirmed that a combination of two of the Milankovitch cycles conspire to start and stop ice ages. The 100,000-year eccentricity cycle amplifies the influence of the 23,000-year wobble of Earth's spin axis called precession. The new modeling also suggests that the great accumulation of mass by the North American ice sheet causes the abrupt end of glacial periods. CO2 is involved, but is not determinative, in the evolution of the 100,000-year glacial cycles say the scientists.
Scientists who study climate will tell you that today's warm temperatures and mild conditions are not normal for Earth during the past several million years. Our planet has been in a general cooling trend for 35 million years and in the grip of an Ice Age for the last 1.6 million years. What's more, this Ice Age, known as the Pleistocene, consists of relatively short periods of warmth, called interglacials, separated by much longer periods of bitter cold, referred to as glacials. The recorded history of humankind covers only the later half of the most recent interglacial warming, though our ancient ancestors did leave messages in the form of cave art that date back to much colder times, times when the Ice Age held the world fast in its frozen embrace. Predicting the timing and duration of these periods remains a problem for scientists. Why the glacial periods should last around 100,000 years, as they have for the last million years or so, is called the 100-kyr problem. Now, a group of researchers claim they know the answer.