This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

This past week, IPCC’s Nobel Prize-winning scientists met in Valencia, Spain to write a synthesis of their three-volume report. The Summary for Policymakers of the Synthesis Report [PDF] makes it very clear that we need to act immediately to avoid the worst effects of global warming.

IPCC Chairman Dr. Rajendra Pachauri summarized the main message as follows: "Climate change is a serious threat to development everywhere. Today, the time for doubt has passed. The IPCC has unequivocally affirmed the warming of our climate system, and linked it directly to human activity. Slowing or even reversing the existing trends of global warming is the defining challenge of our age."

Read more »

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

Last month, Michael explained why we need to cut emissions as soon as possible. A new paper published in the Proceedings of the National Academy of Sciences adds even more urgency. It says that:

• Carbon dioxide (CO₂) emissions from fossil fuel use have accelerated since 2000, and
• Earth's oceans may be taking up an increasingly smaller fraction of the extra CO₂.

This paper received coverage even before it was published. Now that it's out, let's take a closer look.

Read more »

This post is by James Wang, Ph.D., a climate scientist at Environmental Defense.

A study by Weaver et al., published this month in the journal Geophysical Research Letters, reports that "All emission targets considered with less than 60% global reduction by 2050 break the 2.0°C threshold warming this century…." (They mean 2.0°C above the pre-industrial temperature, equivalent to 2.3°F above today's temperature. For more on threshold temperatures, see "How Warm is Too Warm?") Even more disturbing, they say, "Even when emissions are stabilized at 90% below present levels at 2050, this threshold is eventually broken."

That makes all our efforts seem hopeless. But are they right? In a word, no. Here's why.

Read more »

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

Yesterday's New York Times Magazine had an article aptly titled "The Future is Drying Up", about the threats that climate change and booming populations pose to precious water resources in western states. Usually when we think of water and climate change we think of rising sea levels, but climate change is also causing drops in drinking water supplies.

Read more »

This post is by Michael Oppenheimer, Ph.D., the Albert G. Milbank Professor of Geosciences and International Affairs in the Woodrow Wilson School and the Department of Geosciences at Princeton University. He also serves as science advisor to Environmental Defense.

We're already seeing environmental changes from global warming, and some key ones are occurring more quickly than scientists expected. Consequently, many experts from diverse disciplines are uncomfortable with the slow pace of governments in addressing this issue. The growing sense of urgency arises from two concerns:

• Earth's climate system may be rapidly approaching a point of no return where large, irreversible and destructive changes, like the gradual disintegration of an ice sheet, become inevitable.
• To achieve any given temperature goal, the longer we delay action, the steeper emissions reductions will need to be. It's easier to cut emissions gradually than it is to slash them drastically.

Read more »

The author of today's post, Michael Oppenheimer, Ph.D., is the Albert G. Milbank Professor of Geosciences and International Affairs in the Woodrow Wilson School and the Department of Geosciences at Princeton University. He also serves as science advisor to Environmental Defense.

"In about a century, some of the places that make America what it is may be slowly erased" by rising sea levels, says an Associated Press news story from last week. In the map of Florida below, some of the most vulnerable areas – which include Cape Canaveral and a big chunk of Everglades National Park – are shown in red.

Source: University of Arizona's Department of Geosciences.

It's not just historic sites that are threatened, but people. Rising sea levels could displace millions in heavily populated coastal areas across the world.

Why are sea levels rising, and what do scientists project for the future?

Read more »

The author of today’s post, Lisa Moore, Ph.D., is a scientist in the Climate and Air program.

On Wednesday, the DailyTech Blog said that an update to a 2004 survey shows that the scientific community is moving away from a consensus that humans are causing global warming. The survey was submitted to the journal Energy and Environment, but is as yet unpublished.

So is it true? In a word, no, because scientific consensus cannot be surmised from subjective surveys.

Read more »

The author of today's post, Lisa Moore, Ph.D., is a scientist in the Climate and Air program.

This past week there's been a lot of buzz about a small correction that NASA made to U.S. temperature data. Some have said, incorrectly, that the new data show that 1934 edges out 1998 as the warmest year on record, rather than 1998 as previously thought. Actually, 1934 edged out 1998 in the old U.S. record, too, although the difference was not statistically significant. My favorite quote on all this is from Tim Lambert, who said in his coverage of the issue that "1998 and 1934 went from being in a virtual tie, to being in a virtual tie".

Climate change deniers have been all over the NASA correction, saying it proves that global warming isn't happening. Of course, that's ridiculous. For one thing, U.S. temperature isn't global temperature. Globally, the warmest year on record is 2005, and the second warmest is 1998. But what should we make of those high U.S. temperatures in the 1930s?

Read more »

The author of today's post, Bill Chameides, Ph.D., is Chief Scientist at Environmental Defense.

This morning, the Wall Street Journal published an Op-Ed by Dr. William Gray titled "Hurricanes and Hot Air". In it, Dr. Gray argues that there is no link between global warming and the recent "increase in major hurricanes".

Unfortunately, this piece has several inaccuracies and omissions. Let me clear them up.

Read more »

The author of today's post, Bill Chameides, is Chief Scientist at Environmental Defense.

Last week in our Suggestion Box we got this question:

I've compiled a NCDC state by state average temperature map and trends from 1895 thru 2006. 1998 was the warmest year, but years since then are showing either the same as 1998 or cooler in most states. How can I explain to people why average temps haven't been warming EVERY year since 1998 instead of going up and down?

This is a good question, and one I get fairly often, so let me try to explain.

Read more »