Posted on 21 September 2013 by John Hartz

Arctic sea ice shrinks to sixth-lowest extent on record

Sea ice cover in the Arctic has shrunk to one of its smallest extents on record, bringing the days of an entirely ice-free Arctic during the summer a step closer.

The annual sea ice minimum of 5,099m sq km reached last Friday was not as extreme as last year, when the collapse of ice cover broke all previous records.

But it was still the sixth lowest Arctic sea ice minimum on record, and well below the average set over the past 30 years of satellite records.

This suggests the Arctic will be entirely ice-free in the summer months within decades, scientists said.

Arctic sea ice shrinks to sixth-lowest extent on record by Suzanne Goldenberg, The Guradian, Sep 18. 2013

Case for climate change is overwhelming

With the IPCC report not yet published, there is already heated debate about what it will say, and about the implications of its findings for human development.

The scientists' statement is unequivocal, and is not based on whatever the IPCC may publish. They say: "The body of evidence indicating that our civilisation has already caused significant global warming is overwhelming."

The statement comes from 12 members of the recently established Earth League, which describes itself as "a voluntary alliance of leading scientists and institutions dealing with planetary processes and sustainability issues".

Case for climate change is overwhelming, say scientists by Alex Kirby for Climate News Network, The Guardian, Sep 16, 2013

My work will go on - Tim Flannery

I see it as a moral imperative to continue my work and tell people that climate change is happening and threatening our country. Australians have a right to independent information.

Abbott may have decimated the Climate Commission, but my work will go on, Op-ed by Tim Flannery, The Guardian, Sep 19, 2013

No, Arctic sea ice has not recovered

Arctic sea ice extent has reached its seasonal minimum, dropping to the sixth-lowest level in the 35-year satellite record. This year’s melt represents a significant gain in sea ice extent from last year — when the ice cover plummeted to a record low — but scientists cautioned that long-term trends are what is most important, with most projections still showing a seasonally ice free Arctic Ocean by the middle of the century, if not sooner. In addition, measurements of sea ice volume are at near-record low levels, indicating that the ice cover is unusually thin and vulnerable. 

No, Arctic Sea Ice Has Not Recovered, Scientists Say by Andrew Freedman, Climate Central, Sep 19, 2013

Obama climate change plan gets first airing in Congress

The Obama administration asserted its authority to move forward on its climate change action plan on Wednesday – with or without new laws from Congress.

In the first airing of Obama's climate plan, a hearing of the House of Representatives was told the Environmental Protection Agency and other government agencies were already authorised to bring in new measures to reduce greenhouse gas emissions.

"We are not doing anything at the EPA and in the climate plan that goes outside the boundaries of what Congress has said is our mission and our authority," EPA administrator Gina McCarthy told a hearing of the house sub-committee on energy and power.

Obama climate change plan gets first airing in front of House sceptics by Suzanne Goldenberg, The Guardian, Sep 18, 2013

Skeptic Groups Launch Global Anti-Science Campaign

Conservative groups at the forefront of global warming skepticism are doubling down on trying to discredit the next big report by the Intergovernmental Panel on Climate Change (IPCC). In recent weeks, they've been cranking out a stream of op-eds, blogs and reports to sow doubt in the public's mind before the report is published, with no end in sight.

"The goal is to inform the public, scientific community and media that the upcoming IPCC report doesn't have all the science to make informed judgments," said Jim Lakely, a spokesman for the Heartland Institute, a libertarian think tank based in Chicago that has been spearheading the efforts.

Heartland gained notoriety last year after running a billboard campaign comparing climate change believers to "Unabomber" Ted Kaczynski, which caused several corporate donors to withdraw support for the group.

Ahead of IPCC Climate Report, Skeptic Groups Launch Global Anti-Science Campaign by Katherine Bagley, Inside Climate News, Sep 18, 2013

The cost of halving emissions by 2050

Human activities like shipping, construction and industry are increasing the concentration of CO2 entering the atmosphere, which research has overwhelmingly shown is heating the planet and changing our climate.

Many studies, including those by the International Energy Agency, suggest that global CO2 emissions are set to pass 50 Giga-tonnes per year by 2050 if there is no further action by governments to reduce them over the coming years.

Now researchers at Imperial have considered what technologies and interventions are required to limit these global CO2 emissions from human activity to 15 Giga-tonnes per year by 2050, a level that many studies show could help to limit global warming to around two degrees Celsius above pre-industrial levels.

Their report concludes that reaching this target will cost $2 trillion per year by 2050, which is about one per cent of the world's GDP in 2050, and considerably less than this if fossil fuel prices increase with time. 

Halving CO2 emissions by 2050: New report says it will cost $2 trillion a year by Emma Critchley, Imperial College London, Sep 19, 2013

The known knowns of climate change

The philosopher Daniel Dennett once compared science to the construction of a huge pyramid. Its base comprises the mass of well-established knowledge – no longer controversial and seldom discussed outside academia. More recent research is piled toward the top of the pyramid, where most public debate takes place. It is an apt metaphor for climate-change research, and one worth bearing in mind with the publication of the latest report of the United Nations Intergovernmental Panel on Climate Change(IPCC).

The IPCC’s fifth report, the product of several years of work by hundreds of climate scientists around the world, reviews our established understanding of climate change and explains more recent findings. The media understandably tend to focus on the latter – like the much higher sea-level rise predictions compared to the previous IPCC report of 2007. But let us step back from the news cycle to look at the solid knowledge base of our pyramid.

The Known Knowns of Climate Change by Stefan Rahmstorf, Project Syndicate, Sep 18, 2013

Today's Leaders Will 'Determine the Fate of Humanity'

New researchco-authored by leading U.S. climate scientist James Hansen, a longtime employee of NASA who recently resigned to engage in climate activism, paints a grim picture of a future Earth left virtually uninhabitable by current warming trends. The paper, published Monday, concludes that energy-related decisions being made by today’s government leaders will ultimately “determine the fate of humanity.”

Hansen’s paper, authored with several former NASA colleagues, warns that Earth’s climate-regulating systems may be more sensitive to higher levels of carbon than scientists previously suspected. They also calculated the atmospheric changes that would be produced by burning off the estimated stock of Earth’s fossil fuel reserves, finding that it would result in a planetary apocalypse.

“Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change,” they write. Such a scenario, with average temperatures rising 16 degrees Celsius on land and 30 degrees Celsius at the poles, would leave just a fraction of humanity clinging to life atop Earth’s highest ridges, Hansen et. al. predict.

Top Climate Scientist: Today’s Leaders Will ‘Determine the Fate of Humanity’ by Stephen C Webster, Common Dreams, Sep 19, 2013

UN makes high-risk attempt to break deadlock on talks

The United Nations secretary general is to invite world leaders next week to an unprecedented summit on climate change, in the hope of breaking the long deadlock on global warming talks. The high-risk strategy will put heads of state and government together to talk about the issue for the first time since the Copenhagen summit in 2009 ended in scenes of farce and disarray.

Ban Ki-moon has decided he must convene the meeting because of the stalemate in the talks for the past four years, with international action dwindling even as greenhouse gas emissions continue to rise strongly, and scientific warnings over the consequences grow more strident.

He will tell world leaders next week that he expects them to attend crucial talks in 2014, ahead of a diplomatic push for a new global treaty on the climate, to culminate the following year. It is understood that he thinks one of the failures of the Copenhagen process was to bring in leaders only in the dying days of those negotiations, when diplomats had already failed to secure a deal.

Climate Change: UN makes high-risk attempt to break deadlock on talks by Fiona Harvey, The Guardian, Sep 20, 2013

What is the climate change context behind the Colorado floods?

After a weather event as extreme and record-breaking as the recent rainfall and flooding in northern Colorado, the question often arises: Was climate change to blame?

Answering questions like this is part of an effort to place the consequences of climate change in terms that people understand. Two degrees of warming worldwide seems abstract, but bridge-collapsing, home-destroying, killer floods are the sorts of weather events that can bring the impact of climate change home.

The science of linking extreme events to climate change is relatively young. Practitioners in this field, called attribution science, work to understand whether any part of an event like a flood, drought or heat wave can be attributed to climate change.

What is the Climate Change Context Behind the Colorado Floods?by Stephanie Paige Ogburn and ClimateWire, Scientific American, Sep 18, 2013

What's the best way of communicating climate change uncertainties?

The first of the blockbuster Intergovernmental Panel on Climate Change (IPCC) reports is due to be published next week, and already the debate is hotting up over two key uncertainties: how much temperature rise can we expect, and how much the sea level might increase. 

As much of the debate about climate change concerns the future, there are bound to be degrees of uncertainty about the timing, pace and severity of possible impacts.  But how should scientists communicate them in a way that policy makers and the general public understand them?

What's the best way of communicating climate change uncertainties? by James Painter, Reuters Institute, Sep 18, 2013