Wednesday, June 22, 2011

The Mini-Ice-Age and Global Warming

There have been articles recently about the lack of sunspot activity and the possible link to a mini-ice age. It has been my idea from what I have read that we probably would be in the midst of an ice age if it were not for rise in CO2 due to industry and cars, etc.

"The reality is that, while the sun may well be about to give us a shove in the direction of cool temperatures, the evidence suggests it won't be anything like enough to drown out the warming effects of our greenhouse gas emissions," he said.

Scientists are in no doubt that the sun has been acting oddly in recent years. Sunspot numbers ebb and flow in cycles lasting around 11 years but over the past three years, observable sunspots have been mostly missing.

These spots have been used by scientists to indicate the sun's magnetic activity is diminishing, and that the sun may even be shrinking. Since 2007, visible sunspot activity has stalled, leading researchers to suggest that the next solar maximum (due in 2013) could be a long while coming. Instead, the sun could go into a prolonged lull lasting several decades.

This has happened before, the most famous example is the Maunder Minimum of 1645-1715 when a period of solar inactivity coincided with a "Little Ice Age" -- rivers that were normally ice-free froze and snow fields remained year-round at lower altitudes, according to NASA.

There is plenty of evidence that such "grand minima" cool the Earth and that the sun's sunspot cycle is closely tied to these phenomena...He cites research conducted by the Potsdam Institute for Climate Impact Research in Germany that modelled what would happen to temperatures if a grand minimum started now and continued until 2100. They found that it would lower temperatures by 0.3 °C at most.

Now, when you take into account current greenhouse gas emissions, which are set to raise global temperatures by 2-4°C by 2100, even the most optimistic scenario would see a rise of 2 °C reduced to 1.7 °C. Not an ice age at all, in other words.

The University Corporation for Atmospheric Research has an article Arctic Warming Overtakes 2,000 Years of Natural Cooling with this graph:
New research shows that the Arctic reversed a long-term cooling trend and began warming rapidly in recent decades. The blue line shows estimates of Arctic temperatures over the last 2,000 years, based on proxy records from lake sediments, ice cores and tree rings. The green line shows the long-term cooling trend. The red line shows the recent warming based on actual observations. A 2000-year transient climate simulation with NCAR?s Community Climate System Model shows the same overall temperature decrease as does the proxy temperature reconstruction, which gives scientists confidence that their estimates are accurate....

The new study is the first to quantify a pervasive cooling across the Arctic on a decade-by-decade basis that is related to an approximately 21,000-year cyclical wobble in Earth's tilt relative to the Sun. Over the last 7,000 years, the timing of Earth's closest pass by the Sun has shifted from September to January. This has gradually reduced the intensity of sunlight reaching the Arctic in summertime, when Earth is farther from the Sun.

The research team's temperature analysis shows that summer temperatures in the Arctic, in step with the reduced energy from the Sun, cooled at an average rate of about 0.2 degrees Celsius (about .36 degrees Fahrenheit) per thousand years. The temperatures eventually bottomed out during the "Little Ice Age," a period of widespread cooling that lasted roughly from the 16th to the mid-19th centuries.

Even though the orbital cycle that produced the cooling continued, it was overwhelmed in the 20th century by human-induced warming. The result was summer temperatures in the Arctic by the year 2000 that were about 1.4 degrees C (2.5 degrees F) higher than would have been expected from the continued cyclical cooling alone.

"If it hadn't been for the increase in human-produced greenhouse gases, summer temperatures in the Arctic should have cooled gradually over the last century," says Bette Otto-Bliesner, an NCAR scientist who participated in the study.

If the amount of global warming people are causing was small - a person could argue that the greenhouse effect is being beneficial. But it is not minimal, the CO2 is also causing acidification of the oceans, as well as droughts, and more powerful storms and other problems. At the rate the world is warming, along with related problems, denial about problem solving at this point is quite lame, and in my opinion - obnoxious.

1 comment:

man with desire said...

The Ice Age is not a very old concept. It was not thought of in the 1700s, just like the theory of evolution was not widely known then either. This theory only gained ground in the 1840s when two researchers, Charpentier and Agassiz, tried to explain the forms of the Alps by the theory and later expanded it to apply to the whole of Northern Europe. It is surprising that this theory came to light almost at the same time as Darwin's idea of the origin of species. Both of these theories gained simultaneous attention in the society of that time.

It has been thought that there have been several Ice Ages on the Earth. It has even been said that tropical and hot areas like the Sahara, Africa, Saudi Arabia, Yemen, Australia, India, Madagascar, and South America (as presented in the books Jääkausi (Ice Age) / Björn Kurten and Muuttuva maa / Pentti Eskola, for example) were covered with a large continental glacier tens of millions of years ago. The latest Ice Age is assumed to have started "just" about 500,000 years ago and ended 10,000 years ago. The ice sheets are believed to have covered at their widest 55 million square meters, and the thickness of the ice was at most over 3 kilometers (about 1.8 miles).
What should we think about the Ice Age? Have we any reason to believe in it? Maybe the signs that have been interpreted as signs of an Ice Age were caused by something else? We will now study the mystery of the Ice Age.