See here for a more concise but somewhat dryer version of this analysis.

When regulating emissions of greenhouse gases (GHGs), nations around the world claim to use the GHG concentration stabilization target of 450 parts per million carbon dioxide equivalent (ppm CO2-eq) as recommended by the Intergovernmental Panel on Climate Change in 2007, as their guildline for setting domestic emission reduction targets.

IPCC’s 2007 Fourth Assessment Report asserted that Annex I (developped) countries need to reduce GHG emissions 25- 40% below 1990 levels by 2020, and 80-95% below 1990 levels by 2050, in order to stabilize below 450 ppm CO2-eq concentration, after a temporary overshoot by 50 ppm[19]. Such a stabilization pathway was said to provide a "reasonable chance" of averting warming beyond 2˚C above pre-industrial temperature that would lead to catastrophic consequences on human and ecological systems. Most countries that bothered with a climate legislation dropped the tougher end of the ranges, and touted targets such as 20% below 1990 level by 2020, and 80% below 1990 level by 2050, as aggressive climate policies that supposedly heeds the warnings of IPCC. The current US legislation under consideration, the Waxman-Markey bill, is even worse. (See my posts on that bill here and here.)

Paul Krugman wrote an excellent OP-ED "An Affordable Salvation" on New York Times, April 30, 2009. I wrote a letter-to-editor to comment on it (see bottom).

First, here are the highlights of what he wrote:

"It’s important to understand that just as denials that climate change is happening are junk science, predictions of economic disaster if we try to do anything about climate change are junk economics."

Here is a great dark humor about Earth Day, by ClimateProgress blogger Joe Romm:
http://climateprogress.org/2009/04/19/renameearth-day-humor-triage-i-tol...

My comments to him is below:

I entered my testimony for the State Democratic Platform hearing:
http://massdemsplatform.blogspot.com/2009/01/environment.html#comments

ENVIRONMENT

“At every level the greatest obstacle to transforming the world is that we lack the clarity and imagination to conceive that it could be different.” -- Roberto Unger

1. We recognize that atmospheric greenhouse gases (GHGs), currently at 387 parts per million (by volume) carbon dioxide equivalent (ppmv CO2-e), have already exceeded danger level, and A STATE OF EMERGENCY exists now to return quickly to 300-325 ppmv CO2-e, the level that could allow restoring Arctic sea ice to its area 25 years ago[1]. Even at 350 ppmv CO2-e there is still a 7% risk of exceeding 2 degrees Celsius warming over preindustrial level[2] - the red line of global catastrophic climate change according to IPCC[3], that will likely lead to further, uncontrollable and irreversible climate change due to positive feedback loops of the climate systems. Below 300 ppmv CO2-e is the known historically safe concentration during many past glacial cycles that will keep the Arctic ice cap in the summer, and prevent triggering knock on effects of further warming.

This January 2009 paper published in the Proceedings of the National Academy of Sciences provides strong support for insisting that, we could not afford to allow CO2 to PEAK anywhere near 450ppm, even briefly, let alone STABILIZING at 450ppm (which policy discussions have been aiming for but can't even achieve that[1]). With a peak of 450–600 ppm CO2 followed by complete cessation of emissions (and ignoring the effects of other greenhouse gases), the authors predict 1,000 years of irreversible dry-season rainfall reductions in several regions worldwide comparable to those of the "dust bowl" era, and inexorable sea level rise (which still did not model the rise that will be caused by melting ice cover, which dwarfs the heat expansion sea level rise that is modeled, by far).

This NY Times piece reports on the current scientific understanding that babies actually need to ingest the dirt in their environment (with germs and worms and all those goodies) to help train and instruct their nascent immune system to function properly, and lack of that training leads to increased autoimmune diseases (and possibly other immune deficiencies as well?)
http://www.nytimes.com/2009/01/27/health/27brod.html?em

What the scientists fail to take into account, though, is that today's environment is no longer safe for such evolutionarily developed, health-sustaining instincts. The dust that settles around us today is full of toxic chemicals that are released from coal-fired power plants, municipal waste incinerators, petrochemical industries, mining sites, fossil fuel burning vehecles, including international shipping, commercial and military jets, artillery shells and missiles from wars fought on distant continents, rockets, crude electronic waste recycling sweatshops, etc. etc.