We must all do more to deal with unnecessary demand; scarcity represents the new threat to democracy; now is the time for the comfortable nations to step up and do something about it.

Wise words yesterday from powerful world leaders promising action to relieve food shortages and tackle rising prices.

The first pledge, from UK Prime Minister Gordon Brown, trumpeted a Cabinet Office review of food policy, reported widely as a call to cut the food we waste. German Chancellor, Angela Merkel warned that the food crisis would threaten democracy while US President George Bush wanted us to something about hunger in Africa. What, exactly, wasn’t clear.

Food scarcity is an immeasurably serious matter. For some, it is life or death. For others, like us, it means a little extra on the food bill and a little extra thought about what we buy and where we buy it.

How enlightening it would be to hear these leaders say the same of energy which will also soon be in short supply. They could, because their statements would be equally apt. They should, because the way we squander energy is doing just as much damage.

Saving energy by driving and flying less, using waste heat and low energy appliances, and turning gadgets off when they’re not in use, would significantly cut energy consumption and our carbon emissions.

Measures like these would reduce the need for a massive building programme to generate more low-emission energy. They would help ease the pain of rapidly rising energy bills.

The G8 summit in Japan was the perfect forum for politicians to speak out on energy use as bravely as Gordon Brown has done on food. Monday's UK government report on biofuels has put energy use in the world’s spotlight. As President Bush says: now is the time for the well off to act.

Axing his own country’s subsidies for ethanol, a highly polluting corn-based biofuel, and scrapping Europe-wide targets for increasing the use of fuels like ethanol, would be great places to start.

Not doing this is ignoring the cause of climate change. The alternative is water wars and mass migration which will threaten democracy, and extensive droughts and devastating floods, which will quickly erode the comfort of those who once were comfortable enough to act.