An increasingly large amount of peer-reviewed 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 just two years ago.
Climate Change Is Happening Now
Climate change is no longer a theory to be debated or denied. A large amount of scientific research, published in the last two years, shows that it is occurring right now, around the world:
1. Many physical and biological systems, in multiple locations, are already showing the effects of climate change – these include the timing of lake thawing and freezing, plant flowering, and animal migration and breeding.
2. Increased sea surface temperatures in Atlantic and Pacific Ocean hurricane formation zones (leading to stronger storms) are significantly linked to human-induced warming.
3. Ocean acidification is occurring rapidly, due to carbon dioxide in massive amounts dissolving in seawater. This will have major changes on marine ecosystems and subsequently food security for many countries, especially island nations.
4. Projected sea-level rise this century will be greater than that predicted in 2007 – it will probably rise a metre or more, according to recently published research and expert opinion.
5. The accelerated melting of the Greenland ice sheet that began in the summer of 2004 is conclusively linked to global warming.
6. The West Antarctic Ice Shelf (WAIS) has undergone accelerated melting over the last decade and has suffered 10 major ice shelf collapses during that time.
7. Arctic sea-ice is melting much quicker than previously estimated, and it is likely that the ARctic will be ice-free in summer before 2080.
8. The rate of thawing of the northern permafrost is much faster than previously thought, and it is releasing much more greenhouse gas (methane and carbon dioxide) than expected.
Warming Will Occur For Centuries
The warming that is now occurring is expected to last for many centuries even after all anthropogenic greenhouse gas release stops. This is due to the significant inertia that exists in the atmosphere-ocean system (especially the role of the ocean as a heat sink), and the slow removal of CO2 from the atmosphere (around 25% will remain for > 5000 years).
It remains to be seen whether humanity can work together to prevent the worst effects of global warming before we reach one or more tipping points that trigger runaway global warming.