Cloud research has silver lining

The Cloud experiment is investigating the effects of galactic cosmic rays on clouds and climate. Photo / CERN

In Norwich Giles Oldroyd is looking at legumes. In Geneva Jasper Kirkby is sizing up sun spots. And, at the University of East Anglia, Tim Lenton is gauging geo-engineering schemes.

These are just a few of the thousands of scientists all over the world all working on the same thing - a greater understanding of climate change and ways to mitigate its myriad effects.

At the John Innes Centre in the Norwich Research Park, Oldroyd heads a team investigating how legumes - clovers, peas and beans - manufacture their own nitrogen.

Through genetic modification he's looking at ways to transfer legume genes to other crops such as cereals which don't have the ability and need inorganic fertilisers to grow.

As he points out, the use of fossil fuels to create nitrogen-based fertilisers is a major cost in food production and a big environment sustainability issue. "We're entirely dependent on using inorganic fertilisers because we can't sustain the yields to feed the population."

The fertilisers cause other problems, too, through run-off into waterways and, ultimately, oceans where the influx of nutrients can cause massive plankton growth which in turn depletes oxygen levels and creates so called dead zones.

At Cern, Geneva, home of the Large Hadron Collider, Kirkby is investigating the link between cosmic rays and the climate. He's part of Cloud (Cosmics Leaving Outdoor Droplets) - an experiment with a three-metre diameter aerosol/cloud chamber. It's aim is to understand whether or not cosmic rays can affect the formation of clouds.

It's an experiment that has climate contrarians excited because many see the variation in cosmic rays from sun spots as an alternative explanation for global warming.

It's a highly debated issue as to whether sun spot activity has any contribution to climate change, so one of the reasons to do the experiment is to show whether it's a real effect or not. Either way, the experiment, which gets under way next year, is unlikely to make contrarians happy.

Nobody on the Cloud team is claiming that cosmic rays alone determine the environment. "If there really is an effect then it would simply be part of the climate change cocktail," says Kirkby.

Lenton, a professor in Earth System Science says his research begins with a worrying outlook. "Carbon dioxide is rising at about 2 parts per million (ppm) per year. Even with the strongest possible agreement which I don't think we will get [at Copenhagen] - a global 60 per cent reduction by 2050 - we're still heading for 500ppm which would contribute to a net radiative forcing of 2-4 degrees."

That sort of increase in temperature has many scientists looking at grand, not to mention expensive, schemes to mitigate the effects.

These include farms of giant machines that would literally suck greenhouse gases out of the atmosphere; mirrors in space; and techniques that would mimic the effect of a volcanic eruption by injecting tiny aerosol particles into the stratosphere.

There are ideas to make clouds whiter so they reflect more sunlight, and plans to make land sur grasslands and crops more reflective.

Wacky as many of these sound, Lenton has modelled what some of the more feasible plans might achieve.

Generally, most don't seem worth the effort and many are likely to cause more problems than they solve.

Injecting particles into the stratosphere, for example, would have to be an ongoing process, because over time the particles would fall to earth.

Lenton does see more promise however in techniques to create "sinks" for carbon dioxide - in particular growing plants to get CO2 out of the air and then converting their biomass to both charcoal and biofuels.