07 August 2012


Anthropogenic global warming is here, and it is picking up speed.  Witness the following climate-related headlines from the past few months ~

Wikipedia ~ "Earth's mean surface temperature has increased by about 0.8 degrees Celcius  or dC (1.4 degrees Farenheit or dF), with about two-thirds of the increase occurring since 1980.  Warming of the climate system is unequivocal, and scientists are more than 90% certain that it is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation.  These findings are recognized by the national science academies of all major industrialized nations.

"Climate change models .... indicate that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 dC (2 to 5.2 dF) for their lowest emissions scenario, and 2.4 to 6.4 dC (4.3 to 11.5 dF) for their highest.

"Warming and related changes will vary from region to region around the globe.  The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well as a probable expansion of subtropical deserts.  Warming is expected to be strongest in the Arctic and would be associated with the continuing retreat of glaciers, permafrost and sea ice.  Other likely effects of the warming include a more frequent occurrence of extreme-weather events including heat waves, droughts and heavy rainfall, ocean acidification and species extinctions due to shifting temperature regimes.  Effects significant to humans include the threat to food security from decreasing crop yields and the loss of habitat from inundation.  If global mean temperature increases to 4 dC (7.2 dF) above preindustrial levels, the limits for human habitation are likely to be exceeded in many parts of the world, while the limits of adaptation for natural systems would largely be exceeded throughout the world.  Hence, the ecosystem services upon which human livelihoods depend would not be preserved."

I would add that it is illusory to compartmentalize the impacts on the natural world and on humans.  We are all one system.  Our species is but one of millions of interdependent members of the biosphere.  If there is a single fundamental lesson we should have learned by now, it is that we cannot disturb one lifeform without ripples of consequence to its neighbors, thence to their neighbors, and ultimately to ourselves.  Our excesses in species and habitat destruction are coming back to haunt us, perhaps fatally.  We've already crossed too many critical thresholds to be able to heal the planet to its pre-Industrial Revolution state, or even to its pre-1980 state.  Once each threshold is passed, the momentum of degradation takes on a life of its own.  The shame of it is that the victims aren't limited to humans.  Loss of habitat, shifting climate patterns, and deliberate extermination threaten countless species and ecosystems.  Which in turn increases the threat to humans.  We're doing it to ourselves.

Fasten your seat belts, it's going to be a bumpy ride.

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