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Vast portions of the Taiga and other northern hemisphere forests are dieing. The permafrost is melting and releasing large amounts of methane -- methane is ~20X worse a GHG than is carbon dioxide. Both of these are amplification/feedback loops.
The oceans are becoming more acidic -- and this is killing corral reefs and soon shellfish cannot form their shells. Plankton have died off by about 40% since the late 1950's -- they are the base of the food chain in the ocean.
For the past 600,000 YEARS, the carbon dioxide levels have not gone above 275-280ppm. Starting around 1850 -- when we started burning coal, the levels of carbon dioxide have steadily climbed above that level, and have accelerated when cars became more common. The levels really took off around 1970, and now have climbed past 390ppm. This is 40% increase in a mere 150 years -- the exact same time period of our industrial age.
Hmmm.
Since 1970, the Arctic ice and the Greenland ice and the Antarctic ice have all melted faster and faster. This year for the first time in recorded history, both the northwest and northeast passages were ice free for several months. Russia, Canada, the USA and others have started jockeying for access to the oil and gas that until now has been inaccessible.
Ocean levels have risen, both from increased melting of land ice, and because warmer water is less dense. At least two island nations (Maldives being one) have begun the process of finding other land to buy -- so they can move their countries!
There is about 5% more water evaporation now -- which is another amplification/feedback loop. This is part of the reason that we are seeing record breaking rainfall in many places around the world. We have had at least SIX unprecedented floods here in the USA, this year alone.
Crop yields are *not* generally helped by warmer temperatures. Droughts are more intense. The rate of species extinction is up about 100X what it used to be.
California and Arizona may well run out of water. Georgia and Florida have been in a 20 year dispute over water that have greatly intensified in the past few years. The aquifers under much of the USA have dropped in levels by 100's if not 1,000's of feet. The water level in the Amazon is lower than it ever has been.
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