Among them are several countries with massive forests, including Brazil, China, Colombia, Congo, Indonesia, Russia and the United States. Australia has also signed up to the agreement.
More than $US19 billion ($25.4 billion) in public and private funds have been pledged toward the plan.
British Prime Minister Boris Johnson said that “with today’s unprecedented pledges, we will have a chance to end humanity’s long history as nature’s conqueror, and instead become its custodian”.
Experts and observers said fulfilling the pledge would be critical to limiting climate change, but many noted that such grand promises have been made in the past — to little effect.
“Signing the declaration is the easy part,” UN Secretary-General António Guterres said on Twitter.
“It is essential that it is implemented now for people and planet.”
Alison Hoare, a senior research fellow at political think tank Chatham House, said world leaders promised in 2014 to end deforestation by 2030, “but since then deforestation has accelerated across many countries.”
Forests are important ecosystems and provide a critical way of absorbing carbon dioxide — the main greenhouse gas — from the atmosphere. Trees are one of the world’s major so-called carbon sinks, or places where carbon is stored.
But the value of wood as a commodity and the growing demand for agricultural and pastoral land are leading to widespread and often illegal felling of forests, particularly in developing countries.
“We are delighted to see Indigenous Peoples mentioned in the forest deal announced today,” said Joseph Itongwa Mukumo, an Indigenous Walikale and activist from Congo.
He called for governments and businesses to recognise the effective role Indigenous communities play in preventing deforestation.
Luciana Tellez Chavez, an environmental researcher at Human Right Watch, emphasised that strengthening Indigenous people’s rights would help prevent deforestation and should be part of the agreement.
The EU, Britain and the US are making progress on restricting imports of goods linked to deforestation and human rights abuses, “and it’s really interesting to see China and Brazil signing up to a statement that suggests that’s a goal,” she said, adding that the agreement contains “quite a lot of really positive elements”.
But she noted Brazil’s public statements don’t yet line up with its domestic policies and warned that the deal could be used by some countries to “greenwash” their image.
The Brazilian government has been eager to project itself as a responsible environmental steward in the wake of surging deforestation and fires in the Amazon rainforest and Pantanal wetlands that sparked global outrage and threats of divestment in recent years.
But critics caution that its promises should be viewed with skepticism, and the country’s president, Jair Bolsonaro, is an outspoken proponent of developing the Amazon.
The founder of Amazon — the company, not the rainforest — announced separately that his philanthropic fund was devoting US$2 billion ($2.7 million) to fight climate change through landscape restoration and the transformation of agricultural systems.
“We must conserve what we have, restore what we’ve lost, and grow what we need in harmony with nature,” Jeff Bezos said.
Stark warnings on failure to act
About 130 world leaders are in Glasgow for what host Britain says is the last realistic chance to keep global warming to 1.5 degrees above pre-industrial levels — the goal the world set in Paris six years ago.
Increased warming over coming decades would melt much of the planet’s ice, raise global sea levels and greatly increase the likelihood and intensity of extreme weather, scientists say.
The UK Prime Minister described global warming as “a doomsday device” strapped to humanity.
UN Secretary-General António Guterres told his colleagues that humans are “digging our own graves.”
And Barbados Prime Minister Mia Mottley, speaking for vulnerable island nations, warned leaders not to “allow the path of greed and selfishness to sow the seeds of our common destruction.”
Britain’s Queen Elizabeth II urged the leaders “to rise above the politics of the moment, and achieve true statesmanship.”
“Of course, the benefits of such actions will not be there to enjoy for all of us here today: We none of us will live forever,” she said in a video message played at a Monday evening reception in Glasgow’s Kelvingrove museum.
“But we are doing this not for ourselves but for our children and our children’s children, and those who will follow in their footsteps.”
The 95-year-old monarch had planned to attend the meeting, but she had to cancel the trip after doctors said she should rest and not travel.
The British government said Monday it saw positive signs that world leaders understood the gravity of the situation.
Biden’s methane-busting pledge
The announcement was part of a broader effort with the European Union and other nations to reduce overall methane emissions worldwide by 30 per cent by 2030.
Clamping down on methane flaring and leaks from oil wells and gas pipelines — the focus of the Biden plan — is considered one of the easiest ways to cut emissions.
Reducing methane produced from agriculture, in particular by belching cows, is a trickier matter.
Helen Mountford, a climate expert at the World Resources Institute, said the agreement “sets a strong floor in terms of the ambition we need globally”.
Separately, the United States, Britain, France and Germany announced a plan to provide funds and expertise to help South Africa phase out coal, a major source of greenhouse gas emissions.
South Africa, which gets about 90 per cent of its electricity from coal-fired plants, will receive about US$8.5 billion ($11.45 billion) in loans and grants over five years to roll out more renewable energy.
The announcements were not part of the formal negotiations taking place in Glasgow, but rather a reflection of the efforts by many countries to meet previously agreed targets.
But campaigners say the world’s biggest carbon emitters need to do much more.
Earth has already warmed 1.1 degrees. Current projections based on planned emissions cuts over the next decade are for it to hit 2.7C by the year 2100.
Climate activist Greta Thunberg told a rally outside the high-security climate venue that the talk inside was just ” blah blah blah” and would achieve little.
“Change is not going to come from inside there,” she told some of the thousands of protesters who have come to Glasgow to make their voices heard. “That is not leadership, this is leadership.”