Natural cycles aren’t melting polar ice 

Friday, September 01, 2017

John Babits’ Recorder letter (8/21/17) argues:

Collapse of Antarctic ice shelves has nothing to do with climate change.

Antarctic ice has grown to the largest extent on record.

There are natural warming and cooling cycles, and what we are experiencing is warming after the last glacial period.

CO2 and temperature levels have been just as high without human activity.

What the science says:

“Scientists think that the recent ice shelf collapses in both the Arctic and Antarctica are related to climate change. The peninsula has warmed 2.5 degrees Celsius (4.5 degrees Fahrenheit) since 1950, making it one of the fastest-warming places on Earth.” (National Snow & Ice Data Center)

“The mass of the Antarctic ice sheet has changed over the last several years. Research … from NASA … satellites indicates between 2002 and 2016, Antarctica shed approximately 125 gigatons of ice per year …” (NASA Goddard Space Flight Center)

The “Milankovitch cycle” theory developed in the 1920s describes how variations in Earth’s orbit change how much solar radiation warms Earth. This theory is widely accepted, and explains the glacial/interglacial cycles Earth has experienced over the last 2.5 million years.

“The natural [glacial/interglacial] cycle is range bound and well understood, largely constrained by the Milankovitch cycles. Since the beginning of the industrial age, humankind has caused such a dramatic departure from the natural cycle that it is hard to imagine anyone thinking that we are still in the natural cycle.” (OSS, Open Source Systems, Science, Solutions)

“The last time there was this much carbon dioxide in the Earth's atmosphere, modern humans didn't exist. [The world's seas were up to 100 feet higher than they are today, and the global average surface temperature was up to 11°F warmer than it is now.” (Climate Central)

William Gran