In this guest post Neven Acropolis, the man behind the excellent Arctic Sea Ice blog, looks at the reasons why we need to pay attention to the rapid loss of sea ice in the Arctic Ocean.
Arctic sea ice became a recurrent feature on planet Earth around 47 million years ago. Since the start of the current ice age, about 2.5 million years ago, the Arctic Ocean has been completely covered with sea ice. Only during interglacials, like the one we are in now, does some of the sea ice melt during summer, when the top of the planet is oriented a bit more towards the Sun and receives large amounts of sunlight for several summer months. Even then, when winter starts, the ice-free portion of the Arctic Ocean freezes over again with a new layer of sea ice.
Since the dawn of human civilisation, 5000 to 8000 years ago, this annual ebb and flow of melting and freezing Arctic sea ice has been more or less consistent. There were periods when more ice melted during summer, and periods when less melted. However, a radical shift has occurred in recent times.
Ever since satellites allowed a detailed view of the Arctic and its ice, a pronounced decrease in summer sea ice cover has been observed (with this year setting a new record low). When the IPCC released its Fourth Assessment Report in 2007, it was generally thought that the Arctic could become ice-free somewhere near the end of this century. But changes in the Arctic have progressed at such speed that most experts now think 2030 might see an ice-free Arctic for the first time. Some say it could even happen this decade.
What makes this event significant, is the role Arctic sea ice plays as a reflector of solar energy. Ice is white and therefore reflects a large part of incoming sunlight back out to space. But where there is no ice, dark ocean water absorbs most of the sunlight and thus heats up. The less ice there is, the more the water heats up, melting more ice. This feedback has all kinds of consequences for the Arctic region.
Continue reading “Why Arctic sea ice shouldn’t leave anyone cold”
This stunning view of the Arctic and the northern hemisphere was captured by the Suomi-NPP satellite a couple of weeks ago. You can clearly see where the Arctic sea ice is beginning to melt and break up (the bluish bits of offshore ice). More on the image at the Earth Observatory. Meanwhile, new research indicates that extreme Arctic warming and the break-up of the West Antarctic ice sheet may be closely linked, according to evidence from an amazing lakebed core from Russia’s Lake El’gygytgyn. From the Science Daily report:
Brigham-Grette, the lead U.S. scientist says, “What we see is astonishing. We had no idea that we’d find this. It’s astonishing to see so many intervals when the Arctic was really warm, enough so forests were growing where today we see tundra and permafrost. And the intensity of warming is completely unexpected. The other astounding thing is that we were able to determine that during many times when the West Antarctic ice sheet disappeared, we see a corresponding warm period following very quickly in the Arctic. Arctic warm periods cluster with periods when the Western Antarctic ice sheet is gone.”
Not good news.
Meltdown in the treacle factory (Glenn’s PC) means that episode 10 of everybody’s favourite Climate Show is only available in full by podcast. We’ve resurrected the video of our interview with David Suzuki, the great Canadian environmentalist and campaigner (above), but for the full goodness — a great climate change graphic, Russian heatwave analysis, thoughts on climate communication, John “Skeptical Science” Cook introducing the new politicians’ myths section on SkS and explaining the #1 skeptic delusion (no, it isn’t the sun wot dun it), plus a whole stack of solutions — tidal power, electric motorbikes, biochar for pasture and artificial photosynthesis — you’ll have to listen to the audio version (link below). That means you’ll have to do without the graphics we so lovingly describe, but… they’re all in the show notes below the fold… (Back, with luck with pictures, in two weeks).
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Continue reading “The Climate Show #10: David Suzuki survives tech meltdown”
Atmospheric methane levels continued to increase in 2009, the World Meteorological Organisation’s annual Greenhouse Gas Bulletin (summary PDF) confirmed this week. Methane averaged 1803 ppb over the year, up 5 ppb on 2008, and now contributes 18.1% of the radiative forcing caused by current greenhouse gas levels. The Bulletin suggests that “likely causes were above average wetland methane emissions due to exceptionally warm temperatures at high northern latitudes in 2007 and heavy precipitation in tropical wetlands in 2007 and 2008. However, it cautions that the reasons for the recent increases are not yet fully understood.”
A hint that the rise might be continuing this year is contained in this rather striking graph of methane levels recorded recently at the Mt Zeppelin recording station (a misty mountain?) in Ny Ã…lesund, Svalbard…
Continue reading “The gas almost works (more methane)”
This is a guest post by Anthony Giddens and Martin Rees. Giddens is a former director of the London School of Economics, a fellow of King’s College, Cambridge and the author of The Politics of Climate Change. Rees is president of the Royal Society.
This year has seen outbreaks of extreme weather in many regions of the world. No one can say with certainty that events such as the flooding in Pakistan, the unprecedented weather episodes in some parts of the US, the heatwave and drought in Russia, or the floods and landslides in northern China were influenced by climate change. Yet they constitute a stark warning. Extreme weather events will grow in frequency and intensity as the world warms.
No binding agreements were reached at the meetings in Copenhagen last December. Leaked emails between scientists at the University of East Anglia, claimed by critics to show manipulation of data, received a great deal of attention – as did errors found in the volumes produced by the UN’s Intergovernmental Panel on Climate Change. Many newspapers, especially on the political right, have carried headlines that global warming has either stopped or is no longer a problem.
Continue reading “Wake the world”