Hot Topic has devoted a lot of posts to events in the Arctic over the last northern hemisphere summer. The loss of sea ice was dramatic – there was 25% less ice in September than the previous record, set in 2005. The little graph to the left shows just far off the trend line last year’s September area really was. And as I posted yesterday, recent studies suggest that the Arctic is primed for more significant losses in the near future. If the reduction in summer sea ice continues, there are some pretty major implications for the climate of the northern hemisphere and for our modelling of the global climate, and it’s those things that I want to consider in this post. Please note: I am not a climate scientist, and there are a lot of ifs and handwaves in this argument, but bear with me…
Tag: Greenland
Ice in the sun
Time for an ice update. There’s more bad news about the Arctic sea ice, some interesting video from Greenland, and confirmation that the Antarctic is losing significant amounts of ice. A team lead by James Maslanik of the University of Colorado at Boulder’s Center for Astrodynamics Research has tracked the age of perennial Arctic sea ice (the stuff that survives through summer), and found that since the 1980s the ice has become thinner and younger. Of the ice that survived last year’s melt back, 58% is thin and only 2 to 3 years old:
The portion of ice more than five years old within the multi-year Arctic icepack decreased from 31 percent in 1988 to 10 percent in 2007, according to the study. Ice 7 years or older, which made up 21 percent of the multi-year Arctic ice cover in 1988, made up only 5 percent in 2007, the research team reported. [Science Daily, UC release]
This sets the Arctic up for more rapid ice loss, and makes it much harder for the sea ice to recover to its historic size. Meanwhile, Andy Revkin at the New York Times describes what’s been happening in Greenland [you might have to register, but it’s worth it]. The video from a camera being lowered down a moulin is amazing. That’s our world going down the gurgler (as I said at the HT launch). More from Revkin (and more video) at his Dot Earth blog supporting the article.
In our neck of the woods the news isn’t flash, either. A new study confirms that Antarctica has been losing ice over the last 10 years, and finds that the rate of loss has increased by 75% over that time [Herald]. The East Antarctic ice sheet remains more or less stable, but the West Antarctic and Antarctic Peninsula are losing significant amounts of ice mass – a total of 192 billion tonnes of ice in 2006. Perhaps the most interesting finding is that the mass loss is down to increased glacier flow:
Changes in glacier dynamics are significant and may in fact dominate the ice sheet mass budget. This conclusion is contrary to model simulations of the response of the ice sheet to future climate change, which conclude that it will grow due to increased snowfall.
The Christian Science Monitor provides a good overview of what’s going on south of us here.
Meanwhile, to quote a Prebble, I’ve been thinking, and before too long I shall blog about the implications of what’s happening in the Arctic. More questions than answers – but perhaps we can start thinking about how to get the answers we need. More soon…
Going up
How much will sea level rise over this century? “Don’t know” is a good answer. “Not much” is looking like a bad answer that’s getting worse by the month. Last week a group of Northland Conservation Corps workers rode on a hikoi along Ninety Mile Beach to draw attention to the issue:
Tutor Mike Wikitera and his team erected five signs marking predicted sea level rises by 2030. The group, who rode horses to avoid adding to greenhouse gas emissions, erected the first sign at Shipwrecks Bay and placed the last one at Waipapakauri beach on October 30.
But what are the “likely levels” by 2030? The IPCC’s latest report projects between 18cm and 59cm by the end of the century, but only by excluding a very big unknown – how much ice will melt in Greenland and Antarctica. As more evidence of dramatic melt in Greenland arrives, it’s getting increasingly difficult to rule out multi metre rises. The latest number comes from Professor David Vaughan of the British Antarctic Survey, quoted in the Daily Telegraph [UK]:
Prof Vaughan says the main message is not to panic – the effects of melting will be gradual, in the order of three metres per century if the evidence of the past 20,000 years is anything to go by.
Three metres per century? That’s towards the top end of current speculation. 30cm every ten years, ten times the current rate, compares with 17cm over the last century. Prof Vaughan’s right about panic. It’s not a good option, but extreme concern is certainly justified. For some dramatic pictures of what might happen, check out this Greenpeace report on climate change impacts on Spain, timed to coincide with the IPCC meeting in Valencia to ratify the AR4 synthesis report. To see what 3m might mean for NZ, go here and zoom in on your favourite bit of beachfront property. NIWA’s current advice to local government is to allow for 50cm by 2100. That’s in need of considerable upward revision.
Meanwhile, the impact of sea level rise is not just high tides and wet feet. Salt water intrusion into fresh water coastal aquifers can be bad news for agriculture and drinking water – and the problem may be worse than previously thought, according a new study reported by Science Daily. The BBC covers one of the areas at most risk – Bangladesh – in a new series, documenting a boat journey through the country.
Formerly the weekend roundup
Saturday’s promised omnibus extension never arrived, in part because of the arrival of a big cat on my computer, so here’s a Tuesday update.
Tuesday linkfest
Labour weekend means just that, chez Hot Topic. Catching up with farm work, planting the vege garden, getting a sore back – all in a weekend’s work. But climate change waits for no man, so here’s a compendium of stuff that caught my attention over the last few days.
- Contact Energy has announced plans for a huge – 218 turbine, 650MW – wind farm called Hauauru ma raki, to be built on a remote site south of Port Waikato. NZ turbine builder Windflow Technology has announced plans for new models designed to work in India and China, and Meridian has sent wind experts to Scott Base in Antarctica to advise on building wind turbines to reduce fossil fuel requirements. According to Stuff, they think it could be easier than building in Wellington.
- Still more on the Arctic summer: the NSIDC updates its coverage with some excellent animations, while Cryosphere Today adds an archive of maps of atmospheric conditions over the summer, and introduces a web app that allows iPhone users to monitor sea ice conditions. Another reason why I want one. Technology Review visits Greenland to meet the teams measuring the melt, and down south, satellites spot a huge berg breaking off the Pine Island Glacier.
- On the roof of the world, the Nepali Times reports Kiwi guides describing how the disappearance of ice on the planet’s biggest mountains is changing the climbs.
- Two more good articles from TR: Fixing the Power Grid describes how big batteries (capable of supplying 1MW+ for hours at a time) can provide back up for grid problems, and Tiny Solar Cells looks at nanowire solar cells made by a team at Harvard.
- Carbon emissions from shipping could be as much as twice those from aviation, according to a report from Intertanko. Strong growth in trade has driven emissions to 1.2 billion tonnes oer annum. Meanwhile, the Herald reports on aviation’s attempts to be seen to be more climate friendly – and Richard Branson’s efforts to beat Air New Zealand to the first use of biofuels in jets.
- CO2 absorption in the Atlantic has nosedived, adding to concerns that the ocean carbon sink may be reducing – leaving more of our emissions in the atmosphere [University of East Anglia].
- Coral reef specialists have issued a call to action on the impact of climate change: “We call on all societies and governments to immediately and substantially reduce greenhouse gas emissions. Without targeted reductions, the ongoing damage to coral reefs from global warming will soon be irreversible.â€
- The Daily Telegraph [UK] is in the process of becoming enthusiastically green. Latest evidence is a nifty widget – the Telegraph Earth Pulse – which monitors climate and general environment news.
- A dairy farm can produce as much sewage as a small town (see North & South current issue), but worms can turn it all into mellow compost according to US researchers.
- It looks like a “three-wheeled technicolour shoehornâ€, but the No More Gas will do 75 mph and has a range of 30 miles. OK for getting around town, but I’d still prefer a Tesla Roadster…
- The financial word is getting the climate message: Deutsche Bank thinks that efforts to combat climate change will drive an investment “megatrendâ€, Morgan Stanley estimates that global sales of wind, solar and geothermal power and biofuels could be US$1 trillion a year by 2030, and HSBC is launching a climate change investment fund for investors who want to track companies active in the field.
- HT tends to steer clear of dsicussing peak oil, but the Guardian [UK] covers a new report that claims that we passed peak oil last year, and that global oil production will be halved by 2030. Adds a certain piquancy to energy strategy…