SCIENCE & NATURE BRIEFS

CHINESE THROWAWAY

Almost 30% of food produced for human consumption in China is dumped, with about half the wastage occurring during storage and processing. It is estimated that 350 million tonnes of farm produce each year is either ruined and disposed of before reaching its destination or discarded by consumers, retailers and restaurants. About 45 million tonnes of waste stems from eating out. Researchers recommend reducing portion sizes and encouraging customers to take home leftovers.

LONGLASTING SPONGE

Sponges may have been one of the earliest animals to live on Earth, say researchers who studied a northwest Canadian reef believed to be 890 million years old. They found structures that closely resemble the fibrous skeleton of horny sponges (used to make modern bath sponges) that lived about 90 million years before oxygen levels increased to a level considered necessary to support animal life. If correct, the theory of evolution of early animals depending on oxygen may be debunked.

MEGA EMISSIONS

Twenty-five cities are responsible for emitting more than half of all urban greenhouse gases around the globe despite covering only 2% of the Earth’s surface. Asian cities, particularly megacities such as Shanghai and Tokyo, were found to be the highest emitters of greenhouse gases, and cities in Europe, North America and Australia had significantly higher emissions than those of developing nations. The top two sources were electricity use in buildings and road transport. Railways, aviation and waterways contributed less than 15% of the total emissions.