• A London-based tech start-up is developing a secretive tool designed to limit the impact of air pollution in major cities.

• The source of the world’s biggest underwater pool of the powerful greenhouse gas methane has been discovered in the Pacific Ocean by a team of scientists.

The south-western United States is almost certain to experience a “megadrought” lasting decades if global warming continues unchecked, researchers have warned.

• A new vaccine-based treatment for HIV has succeeded in suppressing the virus in five patients, raising hopes further research could help prevent Aids without the need for daily drugs.

Three-month old Abshir, pictured at Garowe General Hospital in Puntland, Somalia, is suffering from malnutrition-related complications pictures by: Tom Pilston/Save the Children

Endangered penguins are hunting for fish in the wrong place because climate change has prompted sardines and other prey to move to another part of the ocean, researchers have discovered.

• A herd of plains bison has been reintroduced to Canada’s oldest national park, more than a century after the iconic North American animal roamed the Great Plains and eastern slopes of the Canadia

Pollution from the Aberthaw power plant is estimated to have caused the premature deaths of 18,000 people in England and Wales, according to environmentalists.

• Oil giant Shell is to launch a bid to leave the 10 vast concrete legs of three oil rigs standing in the North Sea for up to 500 years after the platforms have been decommissioned.

• Illegal ivory that is less than 70 years old is being sold in the UK, after it is stained with tea to make it look older and bypass legislation.

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