There is a provacative series running in Nature about planertary boundaries and a “safe operating space for humanity”.  Everything in the series is free/open access here.   There is a main article and a series of essays and editorials about the approach.  Note, none of this is peer-reviewed science.  I have mixed feeling about it.  At first, it seemed like a useful framework, at least to scare people.  But after reading the paper and thinking about the boundaries (see the table below) the whole exercise seems arbitrary and subjective.  But when you are a gray-beared elder scientist, with your own institute in Stockholm, I suppose you can say anything you want in Nature or Science.

In this issue of Nature, a group of renowned Earth-system and environmental scientists led by Johan Rockström of the Stockholm Resilience Centre sets out to define boundaries for the biophysical processes that determine the Earth’s capacity for self-regulation (see page 472). The framework presented is an attempt to look holistically at how humanity is stressing the entire Earth system. Provocatively, they go beyond the conceptual to suggest numerical boundaries for seven parameters: climate change, ozone depletion, ocean acidification, biodiversity, freshwater use, the global nitrogen and phosphorus cycles, and change in land use. The authors argue that we must stay within all of these boundaries in order to avoid catastrophic environmental change.

The boundaries are based on existing data. For some processes, such as anthropogenic climate change and human modification of the nitrogen cycle, we may already have crossed the line, and need to back-pedal quickly. For others, such as ocean acidification, we are rapidly approaching a threshold beyond which there may be abrupt and nonlinear changes.

The exercise requires many qualifications. For the most part, the exact values chosen as boundaries by Rockström and his colleagues are arbitrary. So too, in some cases, are the indicators of change. There is, as yet, little scientific evidence to suggest that stabilizing long-term concentrations of carbon dioxide at 350 parts per million is the right target for avoiding dangerous interference with the climate system. Focusing on long-term atmospheric concentrations of the greenhouse gas is perhaps an unnecessary distraction from the much more immediate target of keeping warming to within 2 °C above pre-industrial levels. Nor is there a consensus on the need to cap species extinctions at ten times the background rate, as is being advised.

Change measurements (meters per yr) are median filtered (10-km radius), spatially averaged (5-km radius) and gridded to 3 km over the period 2003–2007

New satellite information shows that ice sheets in Greenland and western Antarctica continue to shrink faster than scientists thought and in some places are already in runaway melt mode.

British scientists for the first time calculated changes in the height of the vulnerable but massive ice sheets and found them especially worse at their edges. That’s where warmer water eats away from below. In some parts of Antarctica, ice sheets have been losing 30 feet a year in thickness since 2003, according to a paper published online Thursday in the journal Nature.

Some of those areas are about a mile thick, so they’ve still got plenty of ice to burn through. But the drop in thickness is speeding up. In parts of Antarctica, the yearly rate of thinning from 2003 to 2007 is 50 percent higher than it was from 1995 to 2003. (Read More @ Associated Press)

Pritchard HD, Arthern RJ, Vaughan DG, Edwards LA (2009) Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets. Nature doi:10.1038/nature08471

I have been worried that the failure of the US Senate to pass a new climate bill would negatively affect discussions in Copenhagen, but maybe Obama can reassure the EU and other nations that the US is committed to fighting climate change:

By Christi Parsons

Reporting from New York City – President Obama this morning issued an appeal to world leaders to help avert “an irreversible catastrophe” in the Earth’s climate, accepting a portion of blame for global warming on behalf of the United States but also urging the world’s biggest polluters to change their ways.

Speaking before a United Nations summit on climate change, the president’s first address to the world body, Obama touted steps the U.S. has taken to slow global warming and attempted to reassure the world that Americans are committed to the cause.

“We understand the gravity of the climate threat,” Obama said. “We are determined to act. And we will meet our responsibility to future generations.”

The president also urged world leaders to work toward an international agreement on global warming as they draw closer to a U.N. summit in Copenhagen the end of this year.

The remarks come at a time of rising concern about progress in those talks. Aides to Obama say things aren’t proceeding as quickly as they would like, and are leaving open the possibility that talks will extend into next year.

While there are dire predictions coming from other quarters — European officials say the talks are close to deadlock — administration officials think there still is cause for hope.

This morning, Obama tried to make the case for it. He ticked off a list of steps the U.S. has taken, including investing economic stimulus money in clean energy projects and raising its vehicle emission standards.

Notably, he did not call for the Senate to pass a bill before the Copenhagen meeting in December, or even to get one out of committee by then.

But the president laid down a personal marker on the issue, speaking in starker terms than he has used in months to describe the risk of not acting.

“The security and stability of each nation and all peoples — our prosperity, our health, our safety — are in jeopardy,” Obama said. “And the time we have to reverse this tide is running out.”

Obama also offered a case for every nation to rise to the challenge, asserting that individual countries can still pursue economic prosperity while doing their part to protect the planet.

“Each of us must do what we can when we can to grow our economies without endangering our planet, and we must all do it together,” Obama said. “We must seize the opportunity to make Copenhagen a significant step forward in the global fight against climate change.”

The poorest nations have more to gain by correcting course, Obama suggested, arguing that they suffer disproportionately from the effects of climate change.

“For these are the nations that are already living with the unfolding effects of a warming planet – famine and drought, disappearing coastal villages and the conflict that arises from scarce resources,” Obama said.

“Their future is no longer a choice between a growing economy and a cleaner planet, because their survival depends on both.”

Chinese President Hu Jintao is also addressing the climate change summit today, in addition to meeting with Obama privately this afternoon.

cparsons@tribune.com

http://c.brightcove.com/services/viewer/federated_f8/1155201977

By JOSH GERSTEIN (Politico)

NEW YORK – President Barack Obama urged world leaders at the United Nations on Tuesday to act swiftly to address climate change, but did not offer a plan, or timetable, to get stalled cap-and-trade climate legislation through the U.S. Senate.

“After too many years of inaction and denial, there is finally widespread recognition of the urgency of the challenge before us. We know what needs to be done,” Obama told fellow heads of state gathered for a climate change summit called by U.N. Secretary General Ban Ki-Moon.

“The journey is long. The journey is hard,” Obama added. “We don’t have much time left to make that journey.”

In advance of a key climate-change conference this December in Copenhagen, Denmark, many diplomats and environmentalists were hoping that Obama would detail his strategy to move House-approved carbon-emissions trading legislation through the Senate and onto his desk to be signed into law. But Obama only made a vague pledge to keep pushing for the measure.

“The House of Representatives passed an energy and climate bill in June that would finally make clean energy the profitable kind of energy for American businesses and dramatically reduce greenhouse gas emissions,” Obama explained. “One committee has already acted on this bill in the Senate, and I look forward to engaging with others as we move forward.”

Obama said little about the resistance in the Senate, but indicated the recent economic slump has left some lawmakers reluctant to impose emissions charges that could affect a weakened economy.

“We seek sweeping but necessary change in the midst of a global recession, where every nation’s most immediate priority is reviving their economy and putting their people back to work. And so all of us will face doubts and difficulties in our own capitals as we try to reach a lasting solution to the climate challenge,” Obama said. “But I’m here today to say that difficulty is no excuse for complacency. Unease is no excuse for inaction.”

The president insisted his administration has taken a series of important, groundbreaking actions to fight global warming, such as increasing fuel economy standards and directing stimulus funds and tax credits to energy efficiency.

“Taken together, these steps represent an historic recognition on behalf of the American people and their government,” he said. “We understand the gravity of the climate threat. We are determined to act. We will meet our responsibility to future generations.”

Obama also reminded his international audience that his administration’s support for action on the issue was a break with that of his predecessor, Republican George W. Bush, whose appointees were often openly skeptical about the urgency of the climate-change problem.

“It is true that for too many years, mankind has been slow to respond to or even recognize the magnitude of the climate threat. It is true of my own country as well. We recognize that,” Obama said. “But this is a new day. It is a new era.”

The president signaled that any global treaty to address climate change must include commitments from emerging economies, such as China and India that were omitted from the first international treaty, the Kyoto Protocol.

“We cannot meet this challenge unless all the largest emitters of greenhouse gas pollution act together,” Obama said. “There is no other way.”

Speaking in advance of Obama’s address, Greenpeace spokesman Kert Davies said administration officials were tallying up a variety of less important actions on climate change to divert attention from the inaction on cap-and-trade.

“They’ve gathered this bag of Christmas ornaments they took to Copenhagen, saying, ‘Look, we can do all these things,’ ” Davies said. “We would say Obama needs to exert more leadership and push.”

I’ve blogged about the ongoing discussions between British journalist George Monbiot and Australian geologist Ian Plimer before (see “Monbiot succeeds in moving heaven and earth“), but the dialogue keeps getting better and better:

Creationists and climate change deniers have this in common: they don’t answer their critics. They make what they say are definitive refutations of the science. When these refutations are shown to be nonsense, they do not seek to defend them. They simply switch to another line of attack. They never retract, never apologise, never explain, just raise the volume, keep moving and hope that people won’t notice the trail of broken claims in their wake.

This means that trying to debate with them is a frustrating and often futile exercise. It takes 30 seconds to make a misleading scientific statement and 30 minutes to refute it. By machine-gunning their opponents with falsehoods, the deniers put scientists in an impossible position: either you seek to answer their claims, which can’t be done in the time available, or you let them pass, in which case the points appear to stand. Many an eminent scientist has come unstuck in these situations. This is why science is conducted in writing, where claims can be tested and sources checked.

You either love or hate Monbiot’s relentless approach Plimer giving him the run around , but I admire his tenacity:

I told Plimer that I would accept his challenge if he accepted mine: to write precise and specific responses to the questions I would send him, for publication on the Guardian’s website. If he answered them, the debate would go ahead; if he didn’t, it wouldn’t happen. The two exchanges would complement each other: having checked his specifics, people at the public event could better assess his generalisations.

Plimer refused. After I wrote a blog post accusing him of cowardice, he accepted. I sent him 11 questions. They were simple and straightforward: I asked him only to provide sources and explanations for some of the claims in his book. Any reputable scientist would have offered them without hesitation.

An opportunity for Plimer to dig himself out of a hole? Apparently an missed opportunity:

… instead of answers, Plimer sent me a series of dog-ate-my-homework excuses and a list of questions of his own (you can read both sets on my Guardian blog).

Gavin Schmidt, a senior climate scientist at NASA, examined them and found that most are 24-carat bafflegab, while the rest have already been answered by other means.

Monbiot gets this part spot on:

There is nothing unusual about Ian Plimer. Most of the prominent climate change deniers who are not employed solely by the fossil fuel industry have a similar profile: men whose professional careers are about to end or have ended already. Attacking climate science looks like a guaranteed formula for achieving the public recognition they have either lost or never possessed. Such people will keep emerging for as long as the media is credulous enough to take them seriously.