The Silver Anniversary Of 350

January 21, 2013 glenn Uncategorized

Congratulations, World!  Twenty-five years ago, according to annual mean CO2 data from Mauna Loa Observatory, the earth’s atmosphere achieved the milestone, and threshold, 350 ppm CO2 level.

In the last 25 years, the level has continued to climb.  It is now approximately 395 ppm.  It used to be below 300 a century and a half ago.

This year, we also celebrate the fifth anniversary of the recognition of 350 ppm as a limit, beyond which, “If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects.”

With little effort to reverse the upward trend, there should be pause to consider how long “brief” is.  Hopefully longer than five years.

There are now approximately 800 gigatons (Gt) of atmospheric carbon, and there were around 600 Gt when the atmosphere had less than 300 ppm CO2.  At least 100 Gt carbon would have to be removed from the atmosphere and added to biomass and soil for us to reach or go below 350 ppm CO2.

Most of the stop-global-warming effort has been to reduce greenhouse gas emissions.  If successful, it would take at least the better part of the century for nature to overcome this overshoot and drop the level below the 350 ppm target.  The better part of the century is hardly anybody’s idea of brief.

It should be, but doesn’t appear to be, clear to all concerned that greenhouse gas reductions are not sufficient, and that more abundant life is necessary to draw down atmospheric carbon.  Rapid growing trees and shrubs can capture carbon and store it indefinitely if maintained.  Likewise, grassland species which feed the soil and result in stable topsoil humus can rapidly recycle the carbon we otherwise waste by leaving it in the atmosphere.  We now have an enormous opportunity to enable more life.

Many of us have hope that there will be some significant emission reductions this decade, but whether or not that happens, we can still foster more life.  Not only will that draw carbon out of the atmosphere, but it can help make our planet more resilient, reduce or reverse desertification, prevent extinctions, reduce flooding and drought impacts, and feed people.  (These fringe benefits are clearly necessary, and would be desirable even if global warming weren’t an issue.)  More life is our only real, safe chance to reach or go below the 350 threshold.

Here are the questions we need to answer.  Can we make a dent in the overshoot in the next five years? or even a reversal the next 25? How do we do this?  What kind of effort will it take?

Here are some answers.  It can happen.  More life can do it.  It would take a lot of people doing a lot of work to enable the needed life.

Only time will give us the answer to the next, and most important, question:

Will we?

Visit for information on how to make 350 a reality, or email for presentations or consulting.

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