Is Global Warming Real?

I assume you came here looking for reasons to believe in climate change. Mine are summed up here. For an excellent summary of the history behind the discovery of global warming I recommend this article written by Faye Flam in the 12/14/09 edition of the Philly.com, the electronic version of the Philadelphia Inquirer. A letter written by many of the world's top climate scientists and published in the May 7, 2010, edition of Science Magazine examines the topic of global warming and efforts to deny its reality. It reaffirms the basic scientific consensus concerning the impact of human activity on globla average temperatures.

The main outlines of the scientific consensus on climate change were very nicely summed up in an op-ed essay that appeared in the August 1, 2009 edition of the Sydney Morning Herald. The essay was signed by 15 of Australia's top climate scientists.

I highly recommend reading the entire essay as it is very brief, but in any event what follows are excerpts that convey the main points about the reality and impact of global warming very succinctly (emphasis added).

"Around the world, thousands of scientists have devoted their professional lives to studying the climate. Overwhelmingly, this evidence has led to four conclusions.
The global average temperature has increased by about 0.8 degrees since 1850, with most of the increase occurring since 1950.

The dominant cause of the warming since about 1950 is the increase in the atmospheric concentrations of greenhouse gases released by human activities, of which carbon dioxide (CO2) is the most important.

Warming will increase in the future, if emissions of CO2 and other greenhouse gases maintain their present paths.

Climate change cannot be reversed for many centuries, because of the massive heat stores in the world's oceans.
The heightened concern among climate scientists arises from a growing realisation that climate change can be accelerated beyond current predictions by reinforcing 'climate feedbacks.' When these feedbacks are sufficiently strong they become 'climate tipping points' which can flip the climate into a new state with essentially no way to recover.

Temperature rises above two degrees will be very difficult for contemporary societies to cope with and will increase the level of climate disruption through the rest of the century.

All of these concerns are firmly grounded in science. ... rapid, sustained and effective emissions reductions are required to avoid 'dangerous climate change', regardless of how it is defined.

Higher future emissions increase the risk of crossing climate tipping points and they increase the likelihood that the long-term social and economic costs of both adaptation and mitigation will be higher."