With Ethiopia in the grip of its worst drought in decades, the government has appealed for aid to help the 10 million people living in Africa's second most-populous nation.

A record number of more than 130 countries will sign the landmark agreement to tackle climate change at a ceremony at UN headquarters on 22 April, the United Nations said on Thursday.

In 2012, Ikea made headlines with its pledge to completely power its stores with renewable energy by 2020. Last week, HP, the US-based multinational IT company, made the same pledge, promising to switch completely to renewable by 2020. The fact that both Ikea and HP set the same deadline for renewables, despite the fact that their pledges were separated by four years, illustrates a stunning change in renewable power generation. When Ikea made its promise, it was in the process of installing its own power generation facilities. Four years later, HP has numerous other options.

It also has a lot of company on the renewables bandwagon. As part of its pledge, HP signed on for the RE100 campaign, joining fellow corporations Google, Starbucks, Novo Nordisk and Goldman Sachs. RE100 was launched less than two years ago by a coalition of businesses and nonprofits, but participating companies have, on average, already transitioned half of their energy use to renewables, according to a report released last month – and several companies have already hit the target.

Eighty-five sites on the London Underground are at high and rising risk of flooding, according to a report that says it is “only a matter of time” before serious flooding strikes.

The World Bank has made a “fundamental shift” in its role of alleviating global poverty, by refocusing its financing efforts towards tackling climate change, the group said on Thursday.

More than 250 Malaysian schools were closed on Monday due to a heatwave brought on by the El Nino weather phenomenon which is severely affecting food production and causing chronic water shortages in many countries.

France's oldest nuclear power plant, scheduled for closure in 2018, could be turned into a factory producing electric cars or batteries, the French environment minister said Sunday.

Lake Kariba on the Zambezi River border between Zimbabwe and Zambia used to be dotted with hundreds of commercial fishing rigs, while local fishermen in small makeshift boats would catch enough bream for their livelihood.

Now the fishermen are standing on shore praying for rain as drought has shrunk the water level of the world's biggest man-made lake by volume to a record low.

Global warming could make the planet far hotter than currently projected because today's scientific models do not correctly account for the influence of clouds, researchers said this week.

The study in the journal Science was led by researchers at Yale University and Lawrence Livermore National Laboratory.

More than 120 countries have said they are ready to sign the UN's accord to fight global warming, French ecology minister Segolene Royal said Wednesday.