Category: Climate science

Beautiful haze

ChathamIslands.jpg

I’m a sucker for pictures from space, and this morning’s offering from NASA’s Earth Observatory site is a stunning view of the Chatham Islands, snapped by NASA’s Aqua satellite last Saturday (click on the picture to see the full size image). The turquoise clouds in the sea around the islands are a bloom of coccolithophores, a kind of phytoplankton that plays a significant role in the climate system. They have tiny skeletons made of carbonate, and sequester carbon as they die and their skeletons fall to the ocean floor, but they also affect planetary albedo (by making oceans more reflective), and give off dimethyl sulfide, an important source of particles to seed cloud formation. More here, and here.

I’d be very surprised if this picture doesn’t show up in the newspapers tomorrow, because a) it’s beautiful, and b) NASA doesn’t charge for the use of its images.

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In the heat of the (Arctic) night

LWOct2008.gif Time for an Arctic update and a bit of “original” research. There’s been quite a bit of polar news around, and a rapid freeze-up is underway in the Arctic – so rapid that some are declaring that the sea ice is “back to normal” for the time of year, based on this graph from the Arctic Regional Ocean Observing System in Norway, which shows sea ice area climbing up towards to the average for 1979-2007, within one standard deviation (the grey area). On the other hand, if you look at the equivalent graph at Cryosphere Today, you’ll see that ice area is 1.25m km2 below the average – which in CT’s case is 1979-2000. So the ice is approaching normal, only if you define “normal” as including the significant ice reductions over the last seven years. How encouraging. But this autumn’s freeze-up has been pretty rapid. Does that mean that it’s been unusually cold up there? I thought I’d take a look…

Continue reading “In the heat of the (Arctic) night”

Something in the air (methane mystery)

arcticmethane.jpgAtmospheric methane levels “shot up” in 2007, according to a paper in this week’s Geophysical Research Letters (MIT news release — Rigby, M., R. Prinn, et al (2008), Renewed growth of atmospheric methane, Geophys. Res. Lett., doi:10.1029/2008GL036037, in press. PDF here for AGU members.). This confirms NOAA’s announcement in April that methane levels were on the increase after a decade of stability, but adds a new twist to the data.

One surprising feature of this recent growth is that it occurred almost simultaneously at all measurement locations across the globe. However, the majority of methane emissions are in the Northern Hemisphere, and it takes more than one year for gases to be mixed from the Northern Hemisphere to the Southern Hemisphere. Hence, theoretical analysis of the measurements shows that if an increase in emissions is solely responsible, these emissions must have risen by a similar amount in both hemispheres at the same time.

A rise in Northern Hemispheric emissions may be due to the very warm conditions that were observed over Siberia throughout 2007, potentially leading to increased bacterial emissions from wetland areas. However, a potential cause for an increase in Southern Hemispheric emissions is less clear.

A possible explanation might be a global reduction in the amount of hydroxyl free radical (OH) in the atmosphere. OH “mops up” methane (and other stuff), and is sometimes called the atmosphere’s cleaner or “detergent”. Unfortunately, measuring atmospheric OH is difficult.

“The key thing is to better determine the relative roles of increased methane emission versus any decrease in the rate of removal,” Prinn said. “Apparently we have a mix of the two, but we want to know how much of each” is responsible for the overall increase.It is too early to tell whether this increase represents a return to sustained methane growth, or the beginning of a relatively short-lived anomaly, according to Rigby and Prinn.

Any increase in atmospheric methane is not good news. A possible reduction in OH is also disturbing, because it might indicate that pollution (from all sources, methane, industry, coal burning etc) is beginning to overwhelm the atmosphere’s ability to cleanse itself. Both together would be very bad news indeed.

[Update: Comments from a CSIRO scientist and co-author here.]

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Cloud nine (#2)

kanga.jpg Forty leading Australian scientists have issued an urgent call for action on climate change. Drafted by Barrie Pittock and Andrew Glickson, the statement says that there is a “window of opportunity to halt a climate crisis”, if Australia begins:

Urgently cutting carbon emissions.

Seizing the opportunity to fast-track utilisation of established and new clean energy technologies thus creating new business opportunities.

An urgent tree-planting campaign in Australia and its neighbors.

Attempts at CO2 capture through soil-carbon enrichment and preservation.

The statement has a list of nine suggested policies, including committing (and urging others to commit to) a peak greenhouse gas level of 450 ppm CO2e. Barry Brook at Brave New Climate, one of the signatories, suggests we may need to go further:

We need CO2-e to be 300-325 ppm, and >100% emissions reductions (with active geo-bio-sequestration) as soon as possible. Nothing less is going to pull out out of the sticky mire into which we are now rapidly sinking.

It would be useful if our science community could issue an equivalent statement in the run up to the election, to provide voters with guidance on what can and should be done here – and a yardstick against which to measure policy proposals (or the lack of them). Consider it the scientific equivalent of Treasury’s opening of the national books…

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Down on the farm

20040612-CRW_0583.jpg An Italian olive grove and vineyard is on its way to becoming the world’s first carbon neutral farm (they claim). According to the BBC, the Castello Monte Vibiano Vecchio estate in Umbria is converting to electric vehicles (and biofuelled mini-tractors) and has installed a “solar filling station” designed by Austrian company Cellstrom, based on an array of solar panels feeding a “flow battery” – a new battery technology that allows greatly increased energy storage.

Depending on the amount of usage, the battery centre can store solar-sourced electricity for up to three days. They are working to extend that to 10 days and more, enabling the farm to continue operating through foggy days when the sun does not shine. It means that golf carts and electric bikes will become the key means of transport for farm workers and that they can all charge up at the battery centre.

Cellstrom estimates the farm can save 4,500 litres of petrol every year and reduce CO2 emissions by 10 tons.

According to Lorenzo Fasola Bologna, Monte Vibiano’s chief executive, it will take about five years to recoup the initial investment.

Flow batteries store negative and positive electrolyte solutions (based on vanadium salts) in tanks, and pump them through a reaction cell to charge and discharge. Energy storage is therefore linked to storage tank size, not the number of cells in the system. This makes them ideal as backup storage for wind and solar energy generation, making the energy available even when the sun’s not shining or the wind’s not blowing. New Scientist has a good backgrounder here (behind a paywall, sadly), and there’s also information on the Cellstrom site. Another company in the field is VRB Power Systems of Canada, who have been working with Australian-developed technology.

Back in Umbria, the Italians are covering all their carbon-neutral bases by planting 10,000 trees to mop up any excess emissions.

By the end of next year they hope to be the first farm, anywhere, to reduce their inherent net carbon footprint to zero – ie without using off-site offsetting projects. “It will be great,” says Lorenzo, “to pass on this great, green enterprise to my children and their children.”

Chez Hot Topic we have a vineyard and an olive grove, and I’m already planting trees to offset at least some of our emissions. I wonder if there’s a flow battery in an off-grid future down on our farm?

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