Last month marked the hottest May in modern history, continuing a troubling trend of rising global temperatures, U.S. government scientists said Thursday.

"This was the warmest May on record," said Derek Arndt, chief of the monitoring branch at the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information, during a conference call with reporters.

Pope Francis on Thursday urged the world to act quickly to prevent "extraordinary" climate change from destroying the planet and said wealthy countries must bear responsibility for creating the problem and for solving it.

In a radically worded letter addressed to every person on the planet, the leader of the world's 1.2 billion Catholics blames human greed for the critical situation "Our Sister, mother Earth" now finds itself in.

Human activity is leading to the rapid draining of about one third of the planet's largest underground water reserves and it is unclear how much fluid remains in them, two new studies have found.

Consequently, huge sections of the population are using up groundwater without knowing when it will run out, researchers said in findings that will appear in the journal Water Resources Research and were posted online Tuesday.

Countries need to improve pledges on reducing emissions to reach the goal of keeping the increase in average global temperature below 2C by the end of the century, the International Energy Agency said Monday.

Setting out its assessment of various countries' commitments six months ahead of a crunch climate change conference in Paris, the IEA said: "These pledges will have a positive impact on future energy trends but will fall short of the major course correction required to meet the 2C goal."

From the simplest sketches to the most advanced scientific models, illustrations of mountains pretty much all look the same. Their classic pyramid form, wider at the bottom and narrowing all the way up to the top, has been ingrained in the human mind, and scientists have always assumed that land area in mountain ranges decreases the higher you climb. Until now, that is.

New research published Monday in Nature Climate Change reveals a surprising discovery that not only changes the way we think about mountains but could also have big implications for how we understand, monitor and protect the organisms that call them home.

The marathon effort to forge a world pact on climate change now hinges on what happens outside the U.N. arena in the coming months, analysts said after another faltering negotiation round.

Whether the 195-nation U.N. Framework Convention on Climate Change (UNFCCC) can seal the much-vaunted post-2020 deal in Paris six months from now depends greatly on a flurry of meetings by movers and shakers.

The head of Unilever has called on world leaders to raise their game in the battle against climate change.

Chief executive Paul Polman said governments must set clear CO2 targets to force low-carbon innovation.

As the 2016 presidential election clanks into gear, it's a good time to assess the state of climate change politics in the United States.

In short: Things are not so good. Democrats are largely stuck in an ineffective holding pattern, implementing reasonable reforms with one hand and handing victories to oil companies with the other. Meanwhile, conservatives are still effectively denying the problem exists. Though the movement against climate change is making strides, there is a long ways to go yet.

Royal Dutch Shell has been accused of pursuing a strategy that would lead to potentially catastrophic climate change after an internal document acknowledged a global temperature rise of 4C, twice the level considered safe for the planet.

A paper used for guiding future business planning at the Anglo-Dutch multinational assumes that carbon dioxide emissions will fail to limit temperature increases to 2C, the internationally agreed threshold to prevent widespread flooding, famine and desertification.

Customers generally visit the Marriott hotel near Regent’s Park in London, for a good night’s sleep, not to help fight climate change.

But a radical program of energy demand reduction is underway to help them do both.