Well, here's my links and sources.
I tend to discount those sources at either extreme that either advocate that there is no truth to global warming at all, or appear using it as an issue to promote radical environmentalism.
http://www.citizenjoe.org/sub_tpl.php?sid=25 Is my primary source here and I think it provides some good resources and links.
Climate Change
facts
Few dispute the planet is getting warmer, yet scientists don't all agree on how much humans are responsible for heating things up or on what the effects of a few added degrees to our atmosphere will be. Some predict the worst: flooding, changing weather patterns and even, although remotely, bringing on an early ice age — and they say that humans are largely responsible by burning fossil fuels and cutting down forests. Others say the warnings on global warming are overstated and warn instead that curbing emissions too quickly could end up hurting the American economy and doing little to change the weather. Two policies that are still hanging around for debate are the Kyoto Accords, an international agreement that sets high standards for emissions limits and which the US has not signed on to, and the Climate Stewardship Act, a bill currently in the Senate that would set less aggressive emissions curbs than Kyoto.
General
How much the planet's warming:
Over the past century: 0.5° - 1° F (EPA)
(Note: most of the warming happened before 1940 when temperatures leveled off. Since the 70's surface temperatures have risen again, but not all scientists agree that temperatures in the atmosphere have risen as well.) (EPA and another page from the EPA)
Over the next 50 years: 1° - 4.5° (EPA)
Over the next 100 years: 2.2° - 10° F (EPA)
What's the green house effect?
It's what keeps the earth from being a cool place - the effect of gases in the atmosphere trapping the sun's heat before it bounces back into space, similar to what glass in a green house does. The gases that hold most of the heat are known as green house gases. Here's a graphic from Pew.
How much are humans contributing to global warming?
This is the crux of the debate. Everyone agrees green house gases trap the sun's heat. Everyone also agrees that there are more green house gases in the atmosphere now than there were 150 years ago and that the industrial revolution has a lot to do with that. But, because the earth has its own natural cycles of warming and cooling, scientists disagree on how much the current warming comes from the added gases or from just plain old nature.
Major green house gases, how much they contribute to warming and where they come from (EPA) (Note: because methane and nitrous oxide hold much more heat than carbon dioxide, the percentages below take into account their heat holding effect.):
Carbon dioxide: 83% (almost entirely all comes from fossil fuels);
Methane: 10% (mostly from landfills, natural gas systems and, um, animal digestion);
Nitrous oxide: 7% (mostly from fertilizers;)
Other green house gases have a very small impact.
How much fossil fuels contribute to green house gas emissions (EPA):
Carbon dioxide: 98% comes from fossil fuels;
Methane: 24% comes from fossil fuels;
Nitrous oxide: 18% comes from fossil fuels;
Total: about 85%.
Other - possibly connected - changes over the last century (EPA):
Sea levels have risen 4-8 inches;
Annual rainfall has risen 1%;
Some places getting wetter - others drier (IPCC).
Potential negative effects predicted with climate change:
More water will evaporate, which means more rain and likely more intense rainstorms (EPA);
Soil moisture will likely decline in many areas (EPA);
Sea level will likely rise two feet along most of the U.S. coast (EPA) in the next century and possibly 23 feet in next few centuries (EPA);
More heat waves (EPA).
Potential benefits:
Longer growing seasons (Pew).
Abrupt or "nonlinear" changes:
Because small changes in temperature can tip off large changes in the weather and environment, scientists warn that some effects of global warming are unpredictable. In the short term ecosystems and farming could be thrown out of whack (IPCC). In the long term (over a hundred years away), it's anyone's guess (NRC).
What IPCC says. Because the Intergovernmental Panel on Climate Change is the most widely cited report on global warming, we thought it would be useful to quote what exactly they say about warming:
"There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.”
"Projected climate change will have beneficial and adverse effects on both environmental and socio-economic systems, but the larger the changes and rate of change in climate, the more the adverse effects predominate."
For an analysis of how warming could hurt or help our economy, see Pew's Market Consequences report. The upshot: it could add or take away up to 0.6% of GDP over the next 100 years. You can also see the fed's latest findings on global warming in their August 2004 report Our Changing Planet.
Climate Stewardship Act
What the act calls for:
The latest version of the act, SA 2028, would cap CO2 emissions at 2000 levels by 2010 and would also set up systems for industry to "trade" emissions.
What the economic costs of the act would be on the economy (There are three studies that come to different conclusions):
In 2025: $76 billion (1996 dollars) would be lost from our gross domestic product (EIA) (1996 dollars) (0.4% of GDP);
In 2025: 0.02% of GDP will be lost (MIT, as reported by Pew);
In 2025: $164 billion would be lost a year (CRA).
How that pans out to costs per household:
$525 per household in 2010; $1043 per household in 2020 (CRA);
$15 per household in 2010; $19 per household in 2020 (MIT, as reported by Pew).
You can tell we like Pew - they're a little left of center, but they aim toward balance. For more background on the Climate Stewardship Act, we recommend their fairly detailed overview of Climate Stewardship Act and their responses to the MIT study, the CRA report, and the EIA report.
To see other steps states in the U.S. and across the world are taking to curb emissions, see this chart from Pew.
Where the facts are from:
CRA - Charles River Associates - consulting firm
http://www.crai.com/
EIA - Energy Information Administration - government site
http://www.eia.doe.gov/
EPA - Environmental Protection Agency - government site
http://www.epa.gov/
IPCC - Intergovernmental Panel on Climate Change - international research group
http://www.ipcc.ch/
NRC - National Research Council - part of the National Academy of Sciences, a nonprofit research institute
http://www.nationalacademies.org/nrc/
Pew - Pew Center on Global Climate Change - nonprofit research organization
http://www.pewclimate.org/
