ice sheet

North Atlantic Deep Water Flow Unreliable

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.

Problems With The Pliocene

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.

Forget Global Warming, The Ice Age Is Coming!

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.

West Antarctic Change Indistinguishable From Natural Variability

For some reason a lot of people have become fixated on Antarctic ice—is it waxing or waning, accumulating or melting. Climate alarmists have striven mightily to show that ice at the poles in on the decline, melting in the face of rising global temperatures. Antarctica, with the largest store of glacial ice on the planet, is the primary focus of attention. If Antarctica’s ice sheets were to melt it would be a calamity for mankind. Unfortunately, Earth's climate system contains many cyclic trends, operating on decadal and longer periods of time. In the past, what some claim are clear trends have turned out to be only short term in nature. A new report, just published online, concludes that it is unclear if changes in atmospheric circulation over West Antarctica during the past few decades are part of a longer-term trend. In fact, ice cores reveal a significant increase in the oxygen isotopes from precipitation over the past 50 years, but the anomaly cannot be distinguished from natural climate variability.

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Ice Unknown

It's everywhere on Earth, on the other planets and moons of the solar system, and even in comets from deep space. It is the frozen form of water, commonly called ice. Something so ubiquitous and familiar, one would think that science knows a lot about ice. It turns out science knows less than we might suppose. In a commentary in the journal Nature, an ice scientist raises ten open questions about ice. For example, the article states: “We cannot predict with certainty when and where ice clouds will form in the atmosphere; areas of the sky remain humid when we would expect them to freeze.” Ice is a fundamental part of Earth's climate, yet these questions and others remain unanswered. How can climate science claim to predict the fate of the polar ice sheets or mountain glaciers when we do not really understand the substance that they are made of?

Climatologists Retrench As Climate Refuses To Warm

A newly released study from the Research Council of Norway has climate change alarmists abuzz. One of the things the alarmists have been pushing for is to halt warming at a 2°C increase at any cost (and they mean that literally). In the Norwegian study, much to the alarmists' dismay, researchers have arrived at an estimate of 1.9°C as the most likely level of future warming. The report also recognizes that temperatures have stabilized at 2000 levels for the past decade even though CO2 levels have continued to rise. Meanwhile, a reconstruction of the Eemian interglacial from the new NEEM ice core, published in the journal Nature, shows that in spite of a climate 8°C warmer than that of the past millennium, the ice in Northern Greenland was only a few hundred meters lower than its present level. This finding casts doubt on the projected melting of ice sheets and resulting sea-level rise.

Some Chilling Thoughts

Something happened this year that has become rare in recent times, much of the United States has had a white Christmas. As of December 28th, 64.4% of the US was covered by snow with an average depth of 6.2 inches (15.7 cm). This compares with last month's coverage of only 19.8%. My own town of Conway, Arkansas, received 10 inches on Christmas day and a winter storm advisory is in effect as another storm makes its way eastward. For Arkansas, this has been the snowiest Christmas ever, breaking the old record set in 1926, and the 7th snowiest day overall since 1875. But North America is not alone in feeling winter's bite—record cold continues in Siberia, while a vicious cold snap across Russia and Eastern Europe has claimed nearly 200 lives. What does all this say about global warming?

New Ice Surveys Finds Slower Ice-sheet Melting

A new “comprehensive” report about the melting of Antarctic and Greenland ice sheets is being touted by climate alarmists as “grim news” but in fact says no such thing. This latest estimate, published this week in Science, combines data from many sources including 20 years of satellite data and 32 years of ice-sheet simulations to arrive at a mixed conclusion. It estimates that, between 1992 and 2011, the Antarctic and Greenland ice sheets lost 1350 ± 1010 and 2700 ± 930 Gt of ice, respectively. That is equivalent to an increase in global mean sea level of 11.2 ± 3.8 mm, less than 1/2 an inch. Moreover, while some areas were losing ice mass others were gaining mass from snowfall. The East Antarctic Ice Sheet (EAIS), which occupies over 75% of Antarctica, experienced mass gains during the final years of the study.

Antarctic Peninsula Warming, Time After Time

Over the past 50 years or so, the Antarctic Peninsula, the northernmost part of the mainland of Antarctica, has experienced rapid warming and the collapse of a number of ice shelves. A new temperature record derived from an ice core drilled on James Ross Island, has triggered a reassessment of what triggered the recent warming trends. This new core provides the best record of climate events on the peninsula going back at least 20,000 years, and may extend back as far as 50,000 years. From this new data a team of researchers has constructed the most detailed history of climate on the Antarctic Peninsula known to science and it has revealed a number of interesting things. Most important of these is the fact that this area undergoes bouts of rapid warming periodically and that things were at least as warm on the peninsula 2,000 years ago. So much for “unprecedented” warming on the Antarctic Peninsula.

The Case of the Alternating Ice Sheets

There has been a wave of triumphal announcements by climate change proponents recently, almost giddy over the summer shrinkage of the Arctic ice sheet. “Lowest level ever!” they proclaim, thought that is not quite true. Nonetheless, The Arctic pack ice has been receding over the last decade or so, but that is only natural. You see, there is a well known, if poorly understood, linkage between the ice at the north pole and the ice in and around Antarctica—and the ice around Antarctica is doing quite well. Satellite radar altimetry measurements indicate that the East Antarctic ice sheet interior increased in mass by 45±7 billion metric tons per year from 1992 to 2003. This trend continues today, reinforcing recent scientific investigations into this millennial scale oscillation between the poles. According to studies, this is how things have been for hundreds of thousands of years.

Greenland's Oscillating Glaciers

Melting glaciers are once again in the news, along with the associated threat of rising sea levels. NASA satellites have reported wide spread melting across Greenland which has the climate change alarmists all atwitter. But the NASA satellites are providing data never before available, so it is hard to say if the summer melting pattern is unusual. Meanwhile, some 80 year old scientific data has revealed that this is not the first time that there has been a period of glacial retreat in Greenland. This formerly lost data shows that many land-terminating glaciers underwent a more rapid retreat in the 1930s than in the 2000s. Even more interesting is that the two periods of retreat were interrupted by a period of widespread advance from 1943 to 1972. Greenland's glaciers seem to be oscillating with a period of around a century.

Why Are Sea Levels So Low?

The last interglacial period (LIG)—the Eemian—is commonly believed by scientists to have been warmer than the current Holocene interglacial. Along with that balmier climate there is evidence that sea levels were significantly higher than today. Previous studies have pegged Eemian sea levels at 4 to 6m higher than today. Recently, a new investigation raises that estimate, reporting that ancient sea levels peaked between 6.6 and 9.4 m (~20 to 30 feet). Modern day accounts of flooding in low lying coastal areas and tropical islands abound, with ominous suggestions of links to global warming. How high the oceans will rise is a topic of debate for IPCC members, the news media and assorted climate alarmists, but they are asking the wrong question. Instead, they should ask why are sea levels so low?

The Once & Future Climate?

Between 15 and 20 million years (Myr) ago, Earth's climate took a pause during its long slide into the Pleistocene Ice Age for a period of real global warming. During this relatively brief time glaciers around the world retreated and there are indications that, at least around the edges of the continent, there was significant vegetation on Antarctica. Temperatures may have been as high as 11°C higher than today. Scientists say this global warm spell took place under under CO2 levels in the range of 190–850 ppmv, both significantly higher and lower than today's 390 ppmv. It is hoped that studying conditions during the Miocene warming can provide constraints on the fundamental laws governing the climate system. Why? If the Pleistocene Ice Age is truly coming to an end, as some have said, this may be the climate of the future.

Greenland Glacier Cycle Found

Many of the more strident reports regarding runaway global warming center on rapid ice loss from the glaciers of Greenland. During the early 2000s the Greenland Ice Sheet experienced the largest ice-mass loss since accurate instrument readings have been kept. This was largely caused by the acceleration, thinning and retreat of large outlet glaciers in West and southeast Greenland. Now a new study in Nature Geoscience confirms that ice loss from the Helheim Glacier between 2003 and 2005 was the worst recorded—at least since the last period of rapid ice loss during the late 1930s.

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