Share things

There are two good reasons for eating more fruit and vegetables in place of meat: it’s better for you and it’s better for the environment. Where the food you eat comes from matters less than what it is. The greenhouse emissions from transporting food are typically only a tiny proportion of the total emissions associated with growing food. Livestock are responsible for nearly a fifth of all greenhouse emissions, from the methane produced by their guts and manure, to nitrous oxide emissions from the fertilisers used to grow feed for them. Because it takes several kilograms of plant matter to grow a kilogram of meat, producing meat and animal products such as cheese usually greatly multiplies the environmental damage done by farming. The huge amounts of land required are driving the destruction of rainforests, for instance. Even small reductions in consumption, such as making Mondays meat-free, could make a big difference. If you do eat meat, choose it carefully. Cud-chewing animals such as cattle and sheep are the worst offenders and, surprisingly, grass-fed cattle generally produce even more emissions than grain-fed ones, according to as-yet-unpublished work by Nathan Pelletier of Dalhousie University in Halifax, Canada. Opt instead for chicken, pork or, if you live in Australia, kangaroos. In the US and UK, eating venison could actually reduce emissions where it helps curb burgeoning wild deer populations. And feel free to feast on alien species taking over your neighbourhood, such as the grey squirrels taking over the UK and the Louisiana crayfish invading Arizona. Michael Le Page

Share things

Looking for a romantic way to do your bit for the planet? Then move in with your lover, take baths together and snuggle up on the sofa to watch TV together. An awful lot of energy could be saved if only people shared things more, especially their homes. The evidence comes from the opposite end of the love spectrum. According to a recent study, if all the couples who divorced in the US had stayed together, in 2005 alone they would have used 2373 billion litres less water and 73 billion kilowatt-hours less electricity. Each divorced person spent 46 per cent more on electricity and 56 per cent more on water. Divorce, along with the demise of the extended family, is helping to

Pimp your house Our homes account for around a third of our carbon emissions, so every eco-warrior should try to make their pad a low emission one. It is possible to produce all your own electricity and heat – but only if you have deep pockets and plenty of space for solar panels, wood burning stoves and so on. It makes more sense to reduce your energy needs first. If you use air-conditioning, for example, you should paint your roof white, according to US energy secretary Steven Chu. Its reflective effect could reduce your electricity usage by up to 15 per cent, he says. Simply adding extra insulation, in the loft, in cavity walls and around your hot water cylinder can reduce emissions by as much as a tenth. If you use plant-based insulation, such as hemp batts, you also help keep carbon dioxide out of the atmosphere in another way, locking away about 1.5 kilograms of CO2 per kilogram of conventional insulation replaced. If you are planning an extension, or building a home from scratch, you might even be able to make it carbon negative. Another hemp-based product called hemcrete can be used instead of conventional bricks and mortar, sequestering 110 kilograms of CO2 per cubic metre. Ben Crystall

drive the growth in the number of households, which is accelerating faster than the global population. The good news is that remarriage reduces consumption to pre-divorce levels. Of course, you don’t have to pop the question – living together or sharing with friends works too. After your home, perhaps the next most important thing to share is your car. Lift-sharing schemes can help you find someone who does the same journey as you. And if you don’t need to drive every day, you could swap your car for membership of a car-sharing scheme, a form of car rental. Studies indicate that if you hire a car only when you need it, rather than owning one, you’ll drive a lot less. Valerie Jamieson

Big thinkers, big ideas One thing that could be done to make the world a better place is for citizens to demand that their governments shift the tax burden to fall more heavily on CO2-producing activities. The overall taxes an average person paid would stay the same, so their standard of living would be unchanged, but it would encourage less use of products and services that increase the CO2 concentration in the oceans and atmosphere. Elon Musk, founder of SpaceX and chairman of Tesla Motors

Within hunter-gatherer groups virtually all members possessed the same non-genetic information. Today even the most educated individuals can’t possibly store more than a millionth of 1 per cent of their culture. To make the world a better place, societies must start trying to close the gap. If many more people know the basics of how the world works, civilisation has a much better chance of reaching sustainability. Paul R. Ehrlich, author and population researcher, Stanford University, California

The world population is projected to reach around 9 billion by 2050. If numbers continue to rise beyond 2050, the problems of providing the food, water and energy for an acceptable lifestyle, and of avoiding dangerous climate change, will be aggravated. To make a difference there is no need for the kinds of draconian “population control” that have been implemented in some nations. The social trends that lead to the demographic transition towards lower birth rates include declining infant mortality, availability of contraceptive advice, women’s education, and so forth. It should be an urgent international priority to bring these benefits to impoverished regions. Martin Rees, astrophysicist, University of Cambridge, and president of the Royal Society

19 September 2009 | NewScientist | 33