An increasingly large amount of scientific research, published since the IPCC 4th Assessment Report was released in 2007, shows that climate change is occurring right now, and that it is much faster than predicted only two years ago.
The evidence for this statement is from a multitude of areas. Some of the regions currently undergoing change are shown below.
-Many physical systems, in widespread sites, are already showing evidence of global warming. Examples include the timing of plant flowering, animal breeding, and lake thawing.
-Increased ocean surface temperatures in Pacific & Atlantic hurricane-formation zones which will lead to stronger cyclones are definitely related to human-induced warming.
-Ocean acidification is occurring quickly, due to CO2 in massive amounts dissolving in salty water. This will have major impacts on marine ecosystems and subsequently food supplies for many countries.
-Expected sea-level elevation over the next few decades will be greater than that predicted in 2007. It will probably increase a metre or more, according to recently published research.
-The accelerated melting of the ice sheet in Greenland that started in 2004 has been definitely linked to climate change.
-The West Antarctic Ice Shelf has undergone rapid melting over the last 10 years and has suffered 10 major ice shelf collapses over that time.
-Northern polar sea-ice is melting much quicker than previously estimated, and it is likely that the Arctic will be free of ice in summer within a few decades.
-Permafrost in the Arctic Circle is thawing much quicker than recently thought, and is releasing larger amounts of greenhouse gases than predicted.
The global warming that is now occurring is going to extend for multiple centuries even after all human-released greenhouse gas escape ceases. This is due to the significant inertia that exists in the climate and the delayed decay of carbon dioxide from within the environment.