Greenhouse gases, Climatic modeling, what can be done?

Not Just CO2, Many Others!!

CH4 (methane) N2O (Nitrous oxide – AKA Dinitrogen

monoxide) H2O (Water vapor) O3

CCl3F (Freon 11) CCl2F2 (Freon 12)

Greenhouse factors for these common gases

Substance

Greenhouse factor

Tropospheric Abundance (%)

CO2 1 3.6 X 10-2

CH4 30 1.7 X 10-3

N2O 160 3 X 10-4

O3 2000 4 X 10-6

CCl3F 21,000 2.8 X 10 -8

CCl2F2 25,000 4.8 X 10-8

H2O 0.1 1

Climate change

Very difficult to predict future Many complex, interdependent

factors Poorly understood relationships

Predict local weather accurately? Predict massive climatic change?

Worst case scenario Worst Case Predictions: CO2 in atmosphere increase to ~550 ppm by

2050 Temperature increases 6°C Polar icecaps shrink Oceans rise 15 feet (150 if E Antarctic falls in) – Low countries, islands, cities swamped – 100+°F days in Dallas: 19 increases to 87 – US farmland dries up, Canada thaws out – Mosquitoes, tsetse flies spread disease

Has the greenhouse effect already started? Assess the following statements:

Carbon dioxide contributes to an elevated global temperature.

Concentration of carbon dioxide has been increasing over the past century

The increase in atmospheric carbon dioxide over the past century is a consequence of human activity

There has been an increase in average global temperature during the past century.

Carbon dioxide and other gases generated by human activity are responsible for this temperature increase

The average global temperature will continue to increase as anthropogenic emissions of greenhouse gases increase.

What can be done?

Those that answer this question can be categorized into one of three categories: Must act NOW! Study it more. Don’t act b/c it is inevitable …

“Must act Now” Dr. Stephen Schneider (Stanford)

“… Is this nature being perverse or is it us? The only way to prove for sure is to hang around another 10, 20, or 30 more years, when the evidence would be overwhelming. But in the meantime, we’re conducting a global experiment. And we’re all in the test tube. “

Source – New York Times, December 1997

Further Study William O’Keefe, CEO of the American

Petroleum Institute “ I do not agree that it’s a foregone

conclusion that there’s going to be significant climate change if we don’t take dramatic action now. We also have to reduce the scientific uncertainties. We should not base policy on worst-case scenarios.”

Dr. Michael Oppenheimer, Environmental Defense Fund

“Scientific uncertainties, which are substantial, of course, are not a reason to put off action. In fact, we have only one Earth to experiment on.”

Solutions In contrast to the above mentioned

groups – there are activists – do something NOW and do it FAST! Add sulfate aerosols in the atmosphere – Mt.

Pinatubo in 1991 Fertilize southern oceans in with Iron to

increase growth of phytoplankton MIT scientists propose capturing CO2 and

pumping it into the ocean depths. Princeton Scientists – pump CO2

underground

What can you do?

Conclusions Human actions may have long term

global impact Impact may take decades to reverse Actions require knowledge, thought,

compassion, wisdom Even in the absence of threats like

global warming, solutions to this problem would result in sound, prudent, and responsible stewardship of our planet.