Nations around the world have adopted more than 1,200 laws to curb climate change, up from about 60 two decades ago, a sign of widening efforts to limit rising temperatures, according to a new study.
"Most countries have a legal basis on which future action can be built," said Patricia Espinosa, the UN's climate change chief, at an international meeting on climate change in Bonn, Germany.
She said the findings were cause for optimism, adding that laws were one yardstick for tracking action on global warming, alongside investment in renewable energy or backing the 2015 climate agreement, ratified by 144 nations.
The study, by the London School of Economics (LSE), reviewed laws and executive policies in 164 nations, ranging from national cuts in greenhouse gases to curbs in emissions in sectors such as transport, power generation and industry.
Up to 47 laws had been added since world leaders adopted the Paris agreement to combat climate change in late 2015, a slowdown from a previous peak of about 100 a year between 2009-13 when many developed nations passed laws.
Donald Trump doubts that climate change has a human cause and is considering pulling out of the Paris climate agreement but legislation is often complicated to undo.
"If you have that big body of 1,200 laws it is hard to reverse," said Samuel Fankhauser, the co-director of the LSE's Grantham Research Institute on Climate Change and the Environment.
The study said that developing nations were legislating more but there were still many gaps. Nations including Comoros, Sudan and Somalia have no climate laws.
"We don't want weaklings in the chain," said Martin Chungong, the secretary general of the Inter-Parliamentary Union. He urged all countries to adopt laws that help limit downpours, heatwaves and rising sea levels.