US President Barack Obama (R), actor Leonardo DiCaprio (L) and climate scientist Katharine Hayhoe arrive to discuss the importance of protecting the one planet at South by South Lawn event at the White House in Washington, US, October 3, 2016 – REUTERS

Reuters: A global agreement to combat climate change will take force after support from European nations sent the accord across an important threshold on Wednesday, prompting US President Barack Obama to hail it as a “historic day” for protecting the planet.

European nations, Canada, Bolivia and Nepal raised backing for the 2015 Paris Agreement to countries representing 56.87% of world greenhouse gas emissions, above the 55% needed for implementation, a United Nations website showed.

The deal will formally start in 30 days on November 4, four days before the US presidential election in which Republican Donald Trump opposes the accord and Democrat Hillary Clinton strongly supports it.

China and the United States joined up last month in a joint step by the world’s top emitters.

Obama called Wednesday “a historic day in the fight to protect our planet for future generations” and he told reporters on the White House Rose Garden: “If we follow through on the commitments that this Paris agreement embodies, history may well judge it as a turning point for our planet.”

Germany, France, Austria, Hungary, Slovakia, Portugal and Malta - European Union nations which have completed domestic ratification and account for about four% of emissions - formally signed up on Wednesday.

In total, 73 countries out of 195 have ratified the agreement, according to the U.N. website.

“Great job!” tweeted European Climate Commissioner Miguel Arias Canete.

The Europeans brought forward a formal submission of documents to the United Nations from a ceremony planned on Friday, fearing that other nations might ratify and trigger entry into force without them.

“We didn’t want to be upstaged,” an EU diplomat said.

Many praised the rapid ratification of an agreement meant to cut global greenhouse gas emissions, mainly from burning fossil fuels, to limit floods, droughts, more powerful storms and rising ocean levels.

“What once seemed unthinkable is now unstoppable,” U.N. Secretary-General Ban Ki-moon said in a statement. But all said more work was needed.

“It is no exaggeration to say we are in a race against time,” said Thoriq Ibrahim, Environment Minister for the Maldives and Chair of the Alliance of Small Island States which fears the impact of rising sea levels.

By contrast, it took eight years for the previous UN climate deal, the 1997 Kyoto Protocol, to gain enough backing to take effect. It obliged only rich nations to cut emissions and the United States stayed out of it.

Opposition continues in the Republican-controlled US Congress to Democrat Obama’s climate change policies.

“The Paris climate deal would be disastrous for the American economy,” said House of Representatives Speaker Paul Ryan, a Republican.

By contrast, Paul Polman, CEO of Unilever and Chairman of the World Business Council for Sustainable Development, said ratification showed that a shift to a low-carbon economy is “urgent, inevitable, and accelerating faster than we ever believed possible”.

Still, current national pledges for cuts in emissions are insufficient to achieve a Paris goal of limiting a rise in world temperatures to “well below” two degrees Celsius (3.6 Fahrenheit) above pre-industrial times.

UN studies project that average world temperatures are set to rise by 3 degrees (5.4 Fahrenheit) or more by 2100, based on current trends. And this year is expected to prove the warmest since records began in the 19th century, beating 2015.

How are cities acting on climate change?

LONDON (Thomson Reuters Foundation): The number of cities reporting on their efforts to tackle global warming has jumped 70% to 533 across 89 countries since a new climate change agreement was adopted late last year, according to the group gathering the data.

London-based climate research group CDP said more cities are now doing an inventory of their greenhouse gas emissions with a view to managing them, amid growing awareness of climate risks.

In 2016, four in 10 cities are measuring their emissions, compared with one in 10 five years ago, CDP said in a report released on Tuesday.

Last December, some 195 nations reached a deal to limit global temperature rise to “well below” 2 degrees Celsius by shifting away from fossil fuel use this century.

Here are some facts and figures from the report, which also breaks down the cities’ environmental data by region:

190 cities have set city-level emissions reduction targets, and are taking more than 3,000 actions to limit emissions.

The activities set to generate the biggest emissions reductions are improvements to energy efficiency, including by retrofitting buildings, infrastructure for non-motorised transport, and producing low or zero-carbon energy supplies.

44% of the cities disclosing data have an action plan to curb their emissions.

89% of cities view climate change as a risk to their city, reporting nearly 1,500 actions to adapt to its impacts. Those measures include educating communities, warning and evacuation systems, and flood mapping.

The top climate-related hazards they face include extreme temperatures, storms, floods, water scarcity and insects.

Cities said these climate hazards increase risks to already vulnerable people, and boost demand for public services, including health, as cases of disease rise.

In Africa, just three of the 46 cities reporting have an emissions reduction target, and only 17% have a plan to curb emissions. But 93% view climate change as a significant risk, and nearly two-thirds have, or are working on, a plan to adapt to its impacts. Source: CDP/AECOM 2016 report, “Climate action from 533 global cities”