Assume global warming is real, caused by humans, and can be averted through immediate collective action on the part of all humanity.  How then might we analyse what to do about global warming, based on everything we know?

The return on investment, in terms of time required, cost to implement, and immediate impact to cool the planet, is very good when invested in increasing (nontoxic) aerosol emissions, reforesting the tropics, or cooling the urban heat islands with billions of canopy trees.  The return on investment in reducing carbon emissions, even if completely successful, is more problematic.

Why not emit non-toxic aerosols over the Arctic? Photo: NASA

More aerosols in the atmosphere would be a good way to quickly combat global warming, potentially saving Antarctic ice and immediately ending crippling droughts.  In the book “The Weather Makers” by Tim Flannery, the author cites Mt. Pinatubo’s 1991 eruption as having immediately cooled the planet by 0.3 degrees centigrade (0.5 farenheit).  The same book references an unprecedented increase in temperature in the U.S. during the three-day grounding of commercial aviation after Sept. 11th, 2001.  If we are serious about stopping global warming now, clearly there is a role for aerosols - we just have to invent less toxic aerosols.

Compared to the cost of sequestering CO2 and replacing CO2 emitting sources of fuel, reforesting the tropics and greening the urban heat islands, are less expensive, more feasible, and will yield greater immediate results.  Along with cooling global surface temperatures and increasing land-based CO2 uptake, reforesting and urban forestry will attract rainfall therefore moderating global weather streams more evenly and improving global water supplies. Cooling the world means giving her back her tropical lungs, to move the monsoons.  Cooling the world means trees transforming mega-cities from heat islands burning like rocks in the sun into shaded streams.  Invest in tropical reforesting.  Invest in urban forests.

To focus exclusively on curtailing CO2 emissions is to ration burning and invest trillions in CO2 sequestration schemes - yet fossil fuels are something the world economy is utterly dependent on.  The reason you don’t see pie charts depicting renewable energy sources as a slice of total energy production is because there is only one small slice, hydroelectric, with solar and wind not registering as more than thin lines in the circle.  As of late 2006, most citizens of the world have only begun to live in industrialized societies.  If we focus too much on curtailing CO2 emissions, we will deny aspiring nations their only practical fuel, coal.

Feasible cuts to CO2 emissions may be too little, too late.  Clearly other measures to combat global warming must be considered.  In America, Africa and Asia the tropical forests should expand again, and urban trees should help cool the mega-cities.  In the last 150 years the 56 million square miles of land on earth has seen its forests shrink from 25 to 18 million square miles, deserts expand from 5 to 8 million square miles, and well over a million square miles of urban heat islands sprout across the planet - usually along the rivers where the rain used to fall.  And isn’t it feasible to seed the Arctic from March through September with non-toxic aerosols to save the Polar Bear along with the gulf stream?