CO₂ Level Rise Near-Vertical Now; Warming Impossible to Prevent
by David Sims
EARTH HAS been radiatively unbalanced, absorbing more energy than it radiates into space, since the 1970s, with the oceans absorbing most of the excess heat. This trend will continue for a while, no matter what we do going forward. We can’t prevent global warming now; it is too late. We can, however, make it worse.
In terms of a five-year running average — TRA(y) = [T(y-2) + T(y-1) + T(y) + T(y+1) + T(y+2)] / 5
The running average in the mean global temperature in 2005 was:
* 0.9K higher than that of the Fifth Century.
* 0.7K higher than that of the “Medieval Warm Period” (1000 to 1200).
* 1.4K higher than that of the “Little Ice Age” (1600 to 1800).
* 1.3K higher than that of 1905.
* 0.7K higher than that of 1949.
* 0.3K higher than that of 1990.
If we do everything we can to slow down global warming, it will continue nonetheless to cause Earth’s average temperature to rise by about 1.0K over the rest of the 21st century. If we don’t change our ways at all, the rise will be 3.7K.
The sea level has risen by 0.29 centimeters per year since 1993. The rise has been observed to accelerate during that period. The estimated rise in the sea level over the remainder of the 21st century is expected to be about 75 centimeters.
These are the average estimates.
“It has been estimated that we are already committed to a sea-level rise of approximately 2.3 meters for each degree of temperature rise within the next 2,000 years.” (Source: Wikipedia, which usually doesn’t lie about the physical sciences.)
In the picture (above), the CO₂ concentration in the atmosphere is shown for the past 400,000 years. At no moment within this time period has the concentration been within 100 ppm of what it is now. Likewise, at no other part of this time period has the rate of rise in atmospheric CO₂ been as large as it has been for the past 65 years. Hence, it is likely that the current excess of CO₂ is due to human activity.
It is true that the global level of CO₂ was higher in the distant past, 500 million years ago, than it is today. However, the sun back then was also 5% less luminous than it is now.
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Source: David Sims