Leading scientists warn of surging climate change effects on eve of Copenhagen climate talks.

A group of respected international climate scientists, including those who lead previous studies reported on this website, have issued an update on climate science as of the end of November 2009. The report paints a dire picture of increased greenhouse emissions, heightened effects around the world, and the threat that the world could reach a point of disastrous change if there is no immediate action to limit greenhouse gases.

The major observations include:

Surging greenhouse gas emissions:
Global carbon dioxide emissions from fossil fuels in 2008 were nearly 40% higher than those in 1990. Every year of delayed action increases the chances of exceeding the amount of greenhouse gases which the scientists predict will cause severe and long-term harm to large parts of the earth and its people. Recent global temperatures demonstrate human-based warming: Over the past 25 years temperatures have increased at a rate of .34 degrees F (0.19ºC ) per decade. Even over the past ten years the trend continues to be one of warming.
Natural, short- term fluctuations are occurring as usual but there have been no significant changes in the underlying warming trend.
Acceleration of melting of ice-sheets, glaciers and ice-caps: A wide array of satellite and ice measurements now demonstrate beyond doubt that both the Greenland and Antarctic ice-sheets are losing mass at an increasing rate. Melting of glaciers and ice-caps in other parts of the world has also accelerated since 1990. Summertime melting of Arctic sea-ice has accelerated far beyond the expectations of estimates based on past climate.
Current sea-level rise underestimates: Satellites show global average sea-level rise (3.4 mm/yr over the past 15 years) that is 80% above past predictions. This acceleration in sea-level rise is consistent with a doubling in water flowing into the ocean from melting of glaciers, ice caps and the Greenland and West-Antarctic ice-sheets By 2100, global sea-level increase may well exceed 1 meter.
Delay in action risks irreversible damage: Several vulnerable elements in the climate system (such as continental ice sheets. Amazon rainforest, West African monsoon and others) could be pushed towards abrupt or irreversible change if warming continues as it is now throughout this century. The risk of transgressing critical thresholds (“tipping points”) increase strongly with ongoing climate change.
The turning point must come soon: If global warming is to be slowed to avoid these limits, global emissions need to peak between 2015 and 2020 and then decline rapidly. To stabilize climate, a "decarbonized" global society – with near-zero emissions of CO2 and other long-lived greenhouse gases – need to be reached well within this century. More specifically, the average annual per-capita emissions will have to shrink to 80-95 percent below the per-capita emissions in developed nations in 2000.

The limits and thresholds the scientists speak of is based on a level of 450 parts per million (ppm) of CO2 in the atmosphere, which they say could result in an additional 2 degrees F global temperature increase. There is already 387 ppm of CO2 in the air, and even during the current recession the concentration of the gas has been rising by nearly 2 ppm per year. However, a growing number of scientists are declaring now that the tolerable level of warming and change really is much lower than 450 ppm, and that in fact we already exceed the point of danger. These scientists advocate stopping and reversing the atmospheric concentration back to 350 ppm. This number has become the focus of an international citizens' movement to influence policy and legislation on climate change.