Changes

Scientists such as [[Richard Lindzen]] of MIT, [[Sallie Baliunas]] of Harvard and [[Fred Singer]] (independent) say that the patterns of global warming are naturally caused (see [[climate cycles]]).

Scientists such as [[Richard Lindzen]] of MIT, [[Sallie Baliunas]] of Harvard and [[Fred Singer]] (independent) say that the patterns of global warming are naturally caused (see [[climate cycles]]).

Assessments by the United Nations promote the view that the warming since around 1850 is mostly human-caused.

Assessments by the United Nations promote the world view that the warming since around 1850 is mostly human-caused.

In February, 2007, the [[Intergovernmental Panel on Climate Change]], a body of climate change scientists<ref>http://www.chicagotribune.com/news/nationworld/chi-0704280477apr29,1,4275902.story?coll=chi-newsnationworld-hed</ref> established by the [[United Nations]], released their fourth assessment report on climate change. That report concluded that recent global climate change was "very likely" caused by human activity, <ref>http://news.bbc.co.uk/2/hi/science/nature/6321351.stm</ref>.

In February, 2007, the [[Intergovernmental Panel on Climate Change]], a body of climate change scientists<ref>http://www.chicagotribune.com/news/nationworld/chi-0704280477apr29,1,4275902.story?coll=chi-newsnationworld-hed</ref> established by the [[United Nations]], released their fourth assessment report on climate change. That report concluded that recent global climate change was "very likely" caused by human activity, <ref>http://news.bbc.co.uk/2/hi/science/nature/6321351.stm</ref>.

== Scientists ==

== Scientists ==

[[Image:Rogerrevelle.jpg|thumb|right|100px|Roger Revelle, Al Gore's mentor.]]

[[Image:Rogerrevelle.jpg|thumb|right|100px|Roger Revelle]]

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