A very good read on what new research is producing.
“This study confirms that what was predicted by the models is really happening in the atmosphere,” said Eric Fetzer, an atmospheric scientist who works with AIRS data at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Water vapor is the big player in the atmosphere as far as climate is concerned.”
Yes, there’s certainly more water vapor in the atmosphere today just due to irrigation alone not to mention the thousands of reservoirs we’ve built of the last couple of centuries.
Add to that all of the crops that pull huge amounts of moisture from the soil and put it back in the atmosphere that were not even grown in more than a small percentage of the places they are grown today and that’s a tremendous amount of water vapor.
Additionally the primary discharge from burning fossil fuels is water vapor so again, another huge amount of water vapor added to the natural cycle.
Additionally we have the warming of the oceans which just adds that much more evaporation to the cycle.
Yes, just as we have discussed many times. There are billions of acres producing food crops that put huge amounts of water vapor into the system where previously we had deserts and semi arid regions due to irrigation, not to mention the millions of more acres planted in horticultural plants that are also irrigated and produce the same effect.
We also grow the same crops today in dryland conditions that were never even farmed before further increasing the effect along with all of the WV that is produced through industrialization.
I should also point out that this is why when the glaciers advance during an ice age this is the reason global precipitation falls off dramatically. The driest places on earth are at the poles and places like the Gobi Desert.
It’s hard to keep water vapor in the air in sub zero conditions.
Climate Feedbacks
Greenhouse gases are only part of the story when it comes to global warming. Changes to one part of the climate system can cause additional changes to the way the planet absorbs or reflects energy. These secondary changes are called climate feedbacks, and they could more than double the amount of warming caused by carbon dioxide alone. The primary feedbacks are due to snow and ice, water vapor, clouds, and the carbon cycle.
Snow and ice
Perhaps the most well known feedback comes from melting snow and ice in the Northern Hemisphere. Warming temperatures are already melting a growing percentage of Arctic sea ice, exposing dark ocean water during the perpetual sunlight of summer. Snow cover on land is also dwindling in many areas. In the absence of snow and ice, these areas go from having bright, sunlight-reflecting surfaces that cool the planet to having dark, sunlight-absorbing surfaces that bring more energy into the Earth system and cause more warming.
It took them almost a decade to prove this but indeed they have this year using new technology and new models.
The researchers found that, worldwide, deforestation has decreased the evaporation of water by four per cent. Overall, this is almost exactly offset by the increase in the release of water vapour from irrigation.
No, they said deforestation almost cancels out the increase from agriculture. We’re producing a massive amount of water vapor from other human activities besides agriculture.