Dr. James Hansen has been studying atmospheres since before we knew why Venus is so hot (he was intimately involved in that work).  But in the early 1980s, Hansen's focus shifted to studying our own atmosphere. 

His pioneering work in the analysis of Earth's energy budget resulted in the publication of one of the first predictive works identifying specific impacts that we would face as a result of human-caused climate change.

Hansen's 1981 article in Science Magazine listed those predictions:

• 20th century: Global warming in the 1980s, and subsequent warming by the end of that century which would exceed random noise levels normally seen in weather
• 21st century:  shifting of climate zones (hit the 'Play' button in the lower right-hand corner)
• creation of drought zones
• erosion of ice sheets
• rising sea levels, and
• opening of the fabled Northwest Passage

I've provided links in those predictions.  You can judge for yourself whether Dr. Hansen was correct.  Many of them have happened far faster than even Hansen thought.

Earlier this month, Dr. Hansen gave a 17-minute presentation at the TED Conference.  While I hope that everyone will watch the entire video, I've included a few excerpts from his presentation to whet your appetite, or even just give an overview for those who don't have the time to watch the entire video.

Selected excerpts:

"[Earth's] total energy imbalance now is about six tenths of a Watt per square meter. That may not sound like much, but when added up over the whole world, it's enormous.

It's about 20 times greater than the rate of energy use by all of humanity.

It's equivalent to exploding 400,000 Hiroshima atomic bombs per day, 365 days per year.

That's how much extra energy Earth is gaining each day. This imbalance, if we want to stabilize climate, means that we must reduce CO2 from 391 ppm (parts per million) back to 350 ppm. That is the change needed to restore energy balance and prevent further warming."

...

But instead of placing a rising fee on carbon emissions to make fossil fuels pay their true cost to society, our governments are forcing the public to subsidize fossil fuels by $400 to $500 billion dollars per year, worldwide - thus encouraging extraction of every fossil fuel: mountaintop removal, long-wall mining, fracking, tar sands, tar shale, deep ocean, Arctic drilling.

This path, if continued, guarantees that we will pass tipping points, leading to ice-sheet disintegration that will accelerate out of control of future generations, a large fraction of species will be committed to extinction, and increasing intensity of droughts and floods will severely impact breadbaskets of the world, causing massive famines and economic decline.

Imagine a giant asteroid, on a direct collision course with Earth.

That is the equivalent of what we face now. Yet we dither, taking no action to divert the asteroid, even though the longer we wait, the more difficult and expensive it becomes.

If we had started in 2005, it would have required emission reductions of 3% per year to restore planetary energy balance and stabilize climate this century.

If we start next year, it is 6% per year.

If we wait ten years, it is 15% per year - extremely difficult and expensive, perhaps impossible.

But we aren't even starting."

Watch the video here: