Earth is repeating cooling cycle

Let me fill Joseph N. Bell’s “thimble” of scientific knowledge to overflowing with some real scientific facts (“Motives degrade debate,” Dec. 17).

According to Bell, anyone who doesn’t fall in lock-step behind his chosen selection of “scientists” is a global warming denier akin to a holocaust denier. What a crock!

The Earth has been cooling for 10 years or so. The planet’s climate changes constantly — always has, always will. There have been six ice ages in the last 2 million years, where the level of the seas has fallen 300 feet or more in the glacial period and then have risen 300 feet again in the inevitable warming period that always follows.

The last ice age, the Pleistocene, lasted from 110,000 B.C. to 14,700 B.C. The results of this ice age can be seen everywhere in North America. The glaciers came as far south as Yosemite, where the glaciers carved out the valley and sheared off half of Half Dome. What was once a level area with rivers flowing across the plain before the glaciers, became a valley trough carved out by the glacier for the rivers to now cascade into as the magnificent thousand foot waterfalls we marvel at today.

In the meantime, the water in the Pleistocene glaciers world-wide lowered the sea level in the Bering Straight between modern-day Alaska and Russia to allow the nomads from Mongolia/Russia/Asia to cross the land-bridge into North America and eventually into South America.

As the Earth began to warm again after 14,700 B.C., the glaciers began to recede and the oceans began to fill again thus released from the melting glaciers as it had done five or six times in the last 2 million years. So what caused these dramatic climate changes? It certainly wasn’t mankind spewing man-made carbon dioxide (CO2), because mankind had barely emerged from the caves at this point.

It most likely was the same variations in the sun’s radiation (or lack of it) that provided it as it always has. Carbon dioxide is a minuscule trace gas in the atmosphere, most of which is derived from natural processes. Carbon dioxide in the atmosphere is 0.001% of the total CO2 in the oceans, surface rocks, air, soil and life.

As for Al Gore’s hysterical outburst last week that the polar arctic ice sheets were going to all melt in six years if we don’t do something right now, it might be well for Gore to contemplate for a moment that polar ice has only been present for less than 20% of the Earth’s geological life, while some form of life has been present for 80% of that time and liquid water has been present 90% of that time.

Earth is a warm, wet, volcanic greenhouse planet, which is still recovering from its glacial past. Earth has warmed and cooled constantly on all time-scales.

The climate is always changing and man-made CO2 is a minuscule contributing factor to this change among a myriad of other far more potent contributing sources.

TOM WILLIAMS lives in Newport Beach.