Climate Change Science

Science has awakened us to the reality of climate change. Two decades of painstaking research have accumulated an impressively convincing body of evidence about the reality of man-made global warming and the dangers it poses over the coming century.

Taking an informed view on climate change requires a basic acquaintance with the science. Fortunately there’s lots of clear, accessible material out there. This page aims to introduce you to the best of it.

The Greenhouse Effect:

The core process behind global warming is the “greenhouse effect.” Planet earth is kept warm enough to sustain life by a blanket of greenhouse gases (principally Carbon Dioxide and Methane), which absorb more of the sun’s radiation than they reflect back into space. See the BBC Weather people’s neat explanation.

Impacts:

Since the industrial revolution, we have been producing far more greenhouse gases than before. This has caused a build up of greenhouse gases in the atmosphere (from 280 parts per million of CO2 two centuries ago, to 380 ppm today) and a consequent rise in average global temperatures of 0.6 degrees centigrade over that period.

If these trends continue, likely effects over the coming century include rising average temperatures, increased incidence of floods and storms, severe water and food shortages in many parts of the world, and the danger of genocidal wars over ever scarcer precious natural resources.

The Intergovernmental Panel on Climate Change summarizes these effects in its November 2007 report.

www.realclimate.org is one of the clearest, most authoritative sites on climate science. Here’s their summary of the IPCC’s recent work.

For the BBC’s quick Summary of global impacts,

As a small country on the edge of a desert, Israel is likely to experience more-serious-than-average effects of climate change. Amongst other impacts, Friends of the Earth Middle East project a 30% decline in rainfall by 2050, exacerbating Israel’s already serious water crisis.

Climate Science: Consensus or Controversy?

At Jewish Climate Initiative, our reading of the science is that there is a consensus at least on the following:

  • the climate is undergoing a pronounced warming trend beyond the range of natural variability;
  • the major cause of most of the observed warming is rising levels of the greenhouse gas CO2;
  • a significant part of the rise in CO2 is the result of burning fossil fuels;
  • if CO2 continues to rise over the next century, the warming will continue; and
  • a climate change of the projected magnitude over this time frame represents serious potential danger to human welfare and the environment.

See realclimate.org’s discussion of the consensus position..

This consensus is reflected in the IPCC reports that are compiled by climate scientists from 140 countries and 928 peer reviewed articles on climate change in scientific journals between 1993 and 2003.

A small minority of scientists dispute this consensus position. This is a statement by one of the most vocal, Fred Singer,

Our view is that the climate change denial arguments have been effectively refuted:

How to talk to a climate change skeptic, provides a very useful classification and rebuttal of climate change denial arguments.

Some of the scientists disputing climate change are no doubt sincere. At Jewish Climate Initiative we’re not conspiracy theorist types, but theĀ evidence that many climate change denying scientists and think tanks receive significant funding from the world’s largest oil company is pretty damning.

If there is a remaining area of doubt left in your mind about the conclusions of climate science, that needs to be weighed against the immense human and economic costs of continuing to delay effective action on climate change, if the scientific consensus is right.