Climate Change Dynamics
May 5 2015 ” Climate Change Dynamics”.
Presented by Russ Brown, Corporate and National Laboratory research and development
The IPCC stated that there are only two quantitative measures of climate change, mean surface temperature and sea level.
Natural sea level changes are slow. At present, the current level is close to the historical maximum for interglacial eras. During glacial eras, sea level can drop by as much as 400 feet.
Climate changes between interglacial and glacial era are natural. During the last 800,000 years, the cycles have been on the order of 100,000 years. Earth’s current orbit is a “soft” ellipse, ranging from 91.445 million miles to 94.455 million miles during a year. As the orbit becomes more elliptical, the amount of solar energy received by the planet at it’s most distant point from the Sun could vary by as much as 20-30 percent. While the next glacial era could be delayed and tempered by anthropogenic climate change, the eventual exhaustion of fossil hydrocarbon resources during this interglacial era
could add to the complexity of the planet’s future.
During the following 50,000 years, Earth’s orbit will slowly change from an almost circular configuration to another elliptical one. And so it goes. During the last several cycles, the largest temperature change in the warming eras has been 10 degrees C, or about +0.2 degrees C per 1000 years . . . . except for the last 40-50 years.
Since the 1960-1969 decade, our planet’s temperature rate has been +0.21 degrees C per decade, a a factor of 100 higher. Data from the Goddard Institute of Space Studies-NASA database.
Rapid changes, accompanied with extinctions, have occurred 251, 65, and 55 million years ago from massive volcanism in Asia, a comet strike in Mexico, and a sub-sea continental plate rupture, respectively.
Our current rate of change is associated with rise in the radiative forcing power of carbon dioxide in the atmosphere. It is currently at 397 ppm, an increase of ~70 ppm since the ’70’s.
I will describe the radiative forcing values of carbon dioxide, methane, nitrous oxide, and halocarbons, and will add the large uncertainties associated with the impacts of potential release of methane reserves from arctic tundra and ocean bottoms. Methane is the “sleeping dragon, with a radiative forcing power that is 26.4 times that of carbon dioxide. Any research in that area should involve pilot-scale forcing and extensive mathematical modeling of release under different conditions.