Science a GoGo's Home Page Forums General Discussion Climate Change Forum The Mystery of Global Warming's Missing Heat

The earth's crust is thinnest at the bottom of the ocean.

It has been like that for a long time.

Magma will not suddenly cool over 5 years

Konrad Steffen arrived on the Greenland Ice Sheet for the 2002 summer fieldwork season and immediately observed that something significant was happening in the Arctic. Pools of water already spotted the ice surface, and melting was occurring where it never had before. “That year the melt was so early and so intense — it really jumped out at me. I’d never seen the seasonal melt occur that high on the ice sheet before, and it had never started so early in the spring,” said Steffen, principal scientist and interim director at the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado.

By the end of the 2002 season, the total area of surface melt on the Greenland Ice Sheet had broken all known records. That same summer, Mark Serreze and his colleagues at the National Snow and Ice Data Center in Boulder, Colorado, began noticing unusually low levels of sea ice in the Arctic, based on remote sensing data. “I was really surprised by the change,” Serreze said. “By the end of the summer, sea ice levels in the Arctic were the lowest in decades and possibly the lowest in several centuries.”

Seasonal melt areas on the Greenland Ice Sheet are generally located along the edges of the ice sheet at its lowest points. In 2002, however, the melt started unusually early and progressed higher up the ice sheet than at any time in the past 24 years. Surface melting extended up to 6,560 feet (2,000 meters) in elevation in the northeast portion of the island, where temperatures normally are too cold for melting to occur. In addition, the total melt area covered 265,000 square miles (686,350 square kilometers), representing a 16 percent increase above the maximum melt area measured in the past 24 years.

Serreze’s team coincidentally discovered that in September 2002, Arctic sea ice extent was approximately 400,000 square miles (1.04 million square kilometers) less than the long-term average of 2.4 million square miles (6.2 million square kilometers), and that much of the remaining sea ice was unusually thin and spread out.

It is very unlikely that the 20th-century warming can be explained by natural causes. The late 20th century has been unusually warm.

In terms of the underlying rates of change, the warming of the late 20th century appears to be no more “unusual” than the warming during the 1920’s and 1930’s. Both appear to have their origin in a solar cycle phenomenon in which the sinusoidal pattern in the underlying smoothed trend is modulated so that annual rates of change remain strongly positive for the duration of the third cycle, with the source of this third cycle modulation perhaps related to long term trends in oceanic oscillations. It is purely speculative, of course, but if this 66 year pattern (3 Hale cycles) repeats itself, we should see a long descent into negative territory where the underlying smoothed trend has a negative rate of change, i.e. a period of cooling like that experienced in the late 1800’s and then again midway through the 20th century.

Greenland appears to be floating upwards – its landmass is rising up to 4 centimetres each year, scientists reveal.

And the large country's new-found buoyancy is a symptom of Greenland's shrinking ice cap, they add.

"The Earth is elastic and if you put a load on top of it, then the surface will move down; if you remove the load, then the surface will start rising again," explains Shfaqat Khan of the Danish National Space Center in Copenhagen.

Pressure relief melting - very important!

Magma occupies more space than rock does

Therefore, in order to melt, the rock needs room to expand

This may not be possible where the pressure is too great

That's why the interior of the earth is probably not liquid

A reduction in pressure can cause local melting of rock to form magma

allowing the ocean to cool.

if the ocean does cool,

it would be the area just by the ocean floor that was not monitored.