KEY POINTS:
If you've been paying any attention to the contentious debate around climate change, you'll have heard about some of the alternative energy sources being considered to reduce the blanket of gas we pump into our atmosphere.
There's bio-fuel, which can be created from crops such as corn and
sugar cane and in its purest form is virtually harmless to the environment. Nuclear remains a dirty word here, despite its ability to provide cleaner power. New Zealand is one of the countries that favours wind-powered turbines and solar power is gaining traction.
Then there's that scary-looking device floating on the waves at Port Kembla in New South Wales. It's like a big, iron shack that rises and falls on the swell. As it does so, air rushes in and out of a chamber, spinning a turbine which generates electricity.
Billions will be spent on all these solutions in the coming years, but the coal and gas-fired power stations will still be pumping out CO2 until the cleaner methods make an impact.
In the meantime, we need to reduce global-warming-causing carbon dioxide emissions and some scientists say the way to do that is to go underground, to bottle up the carbon in subterranean cracks and crevices.
It's not as silly as it sounds. After all, we've been tapping oil and natural gas reserves for long enough now to have left many empty cavities deep underground, where the porous stone is good at absorbing and storing gases. Those vast, airtight underground storage chambers held gas for millions of years, so why should pumping gas back into them cause harm? That's the argument, although it has yet to be proven categorically. There are plenty of projects under way, particularly in the US and Europe, looking at the pros and cons of carbon sequestration for power plants.
Between the energy industry and scientists, the cavities under the earth have been accurately mapped, giving a good indication of how much storage capacity exists underground.
But there are a couple of big stumbling blocks to overcome with sequestration. Removing the carbon dioxide from the emissions released through the power station's flue is a tricky and potentially power-intensive task. American Electric Power will extract the carbon dioxide and, under high pressure, convert it into liquid form. It hopes that only 15 per cent of the power stations' energy will be consumed in the process of carbon dioxide extraction, but it could be higher. The more expensive and inefficient the process is, the less likely it is to be adapted by the energy industry overall.
The other issue is finding suitable storage fields close to the power stations to inject the carbon dioxide into.
What will drive development is pressure from the Government to reduce power plant emissions.
But could carbon sequestration come back to bite us?
A natural disaster at Lake Nyos, Cameroon, in 1986, illustrated well what can happen when a concentrated amount of carbon dioxide is released into the air. About 1800 people died when carbon dioxide, possibly triggered by a small earthquake, bubbled up through Lake Nyos and drifted up a nearby valley. Scientists later installed pipes in the lake to allow for degassing of it at regular intervals. Living on a trembling fault line, like the one that runs through New Zealand, the thought of an earthquake cracking open a massive reservoir of carbon dioxide is a scary one. But carbon sequestration, if mastered, could do more to reduce the impact of climate change than many of the other measures proposed so far.
Space for water
Scientists have discovered a distant, Jupiter-like planet made up entirely of gas that also has water vapour in its atmosphere. The find is significant in itself, but would be even more intriguing if rocky planets are discovered close to it as the presence of water could indicate life. The "HD209458b" planet is 150 light years from Earth and appears on images taken by the Hubble telescope. A new analysis of the image by astronomers at Lowell Observatory unveiled the presence of the water vapour.
www.lowell.edu
Google maps tragedy
Google's latest trick has a sobering tone. A Google Earth project focusing on the civil war in Darfur features satellite images of the area complete with icons that show the locations of destroyed villages and refugee camps. Clicking on the icons brings up details of each village and the toll it has suffered in the fighting that has raged for four years and claimed an estimated 200,000 lives.
www.ushmm.org
