Today, the National Research Council (comprised of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine) published its Advancing the Science of Climate Change (2010) America's Climate Choices website. The National Academy of Sciences is comprised of approximately 2100 of the best scientists in the U.S.
To be invited by your peers into the NAS is second only to receiving a Nobel Prize in terms of recognition in science, according to this Wikipedia article on the NAS.
The tofu is below the fold (beef is an extravagant source of protein in terms of carbon footprint).
Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities. from Page 17 of Advancing the Science of Climate Change (2010)
The "very likely" wording is among the strongest levels of wording in science, connoting that there is less than a 1% chance of the opposite being true. In this case, the opposite would be that warming is not due to human activities, not a question about the earth warming- which is an observed trend. The companion report, Limiting the Magnitude of Climate Change (2010), goes into the methods of restricting the impact expected. Another companion report, Adapting to the Impacts of Climate Change (2010), indicates that the first and most impacted are in the poorest areas on earth. Later, the impacts will reach developed low-lying areas, then finally the rest of us. A reasonable assumption is that these effects are evident in the multiple extreme weather events of the past decade. Weather anomalies like 100+ year storms, floods, and droughts; and more frequent and severe tornadoes and hurricanes are consistent with current climate change modeling.
Remember that the Nobel Committee has already spoken, when in 2007 they awarded the Nobel Peace Prize to the International Panel on Climate Change (IPCC) and Al Gore Nobel Peace Prize Announcement from 2007.
The fact of global warming was accentuated last weekend, when NASA data were released demonstrating that March and April 2010 and the January to April 2010 period were the hottest on record (131 years), by far. See Joseph Romm's blog on heat record so far in 2010 and NASA global monthly average temperature data for 131 years.
This may seem counter-intuitive to people who lived in parts of the northeast this past winter, but that is the nature of global average temperatures. One may have a particular weather experience in one location, while the other 778 million square miles of earth's surface are experiencing the opposite.
Updated: to clean up some grammar and get you to read again.