Glasgow, Scotland(CNN) Nearly 120 world leaders gathered in Glasgow on Monday to address what scientists and health experts say is the world's biggest crisis: climate change.
The meeting came on the heels of a G20 summit that delivered, at best, mixed results on climate, with the leaders of the world's richest countries failing to agree on key targets, such as a firm deadline for the end of coal power. But there are some glimmers of hope.
Here are the key takeaways from the first full day of the UN's COP26 climate summit:
The first major commitment to emerge from the conference was a big one: more than 100 leaders, representing more than 85% of the world's forests, agreed to end deforestation by 2030. The deal will be officially announced Tuesday, but a UK government statement confirmed the deal late Monday.
Among the nations taking part in the pledge are Canada, Russia, Colombia, Indonesia, and the Democratic Republic of the Congo, which holds some of the world's most important carbon sinks.
Crucially, Brazil also signed up. A deforestation crisis has ravaged the Amazon in recent years, putting one of the world's most crucial natural defenses against climate change at risk, and the country's President Jair Bolsonaro has been urged both at home and abroad to toughen his response.
President Joe Biden apologized to his fellow world leaders that the United States withdrew from the Paris Agreement under the Trump administration.
"I guess I shouldn't apologize, but I do apologize for the fact that the United States -- the last administration -- pulled out of the Paris Accords and put us sort of behind the 8 ball," Biden said in Glasgow.
Biden reentered the agreement just hours after he was sworn into office in January.
As world leaders delivered their opening remarks, Biden was seated toward the back of the huge plenary room, in keeping with the tradition of seats being allocated in alphabetical order.
"We will demonstrate to the world that the United States is not only back at the table, but hopefully leading by the power of our example," the President said during his own opening address.
But while Biden struck an ambitious tone during his speech, telling attendees his "administration is working overtime to show that our climate commitment is about action, not words," a shadow hung over his climate agenda across the ocean in Washington.
Democratic lawmakers have been debating, and so far failing to agree on, an economic package that includes $555 billion in climate change provisions.
The UK government, which is hosting the UN climate summit in Glasgow, has tried its best to press it upon world leaders that now is the time to act on climate.
The opening ceremony saw Prime Minister Boris Johnson telling his fellow heads of governments that they can be just like James Bond, the famous (albeit fictional) 007 agent.
"We may not feel much like James Bond -- not all of us necessarily look like James Bond -- but we have the opportunity and we have the duty to make this summit the moment when humanity finally began, began to defuse that bomb," he said.
"The Doomsday device is real, and the clock is ticking to the furious rhythm of hundreds of billions of turbines and systems ... covering the Earth in a suffocating blanket of CO2," he said.
Royalty -- both real and of the TV variety -- was also in attendance, with Prince Charles urging leaders to work together, and the celebrated naturalist and broadcaster David Attenborough telling them future generations would judge them by their actions during this conference.
Later in the day, Queen Elizabeth II welcomed world leaders in a video address played during a reception.
"For more than seventy years, I have been lucky to meet and to know many of the world's great leaders. And I have perhaps come to understand a little about what made them special," the Queen said in her address. "It has sometimes been observed that what leaders do for their people today is government and politics. But what they do for the people of tomorrow -- that is statesmanship."
Indian Prime Minister Narendra Modi made headlines on Monday by announcing a net-zero emissions target, pledging India will become carbon neutral by 2070.
While it was a major announcement, as India had not yet put a date on its net-zero ambition, the 2070 target is a decade later than China's, and two decades after the world as a whole needs to achieve net-zero emissions in order to avoid temperatures from rising beyond 1.5 degrees Celsius above pre-industrial times.
But Ulka Kelkar, climate program director at WRI India, an environmental research organization, said that because of India's economic development and energy mix, the target date should not be compared to those of the US or Europe.
"It was much more than we were hoping for," said Kelkar. "Net-zero became a topic of public discourse only six months ago. This is something very new for Indians."
"Just having this concept understood in India is going to give a very strong signal to all sectors of industry," she added.
With India's announcement, all of the world's top 10 coal-power countries have committed to net-zero, according to climate think tank Ember.
Australian Prime Minister Scott Morrison trumpeted his country's work on cutting emissions, claiming that Australia was on track to lower the country's emissions by 35% until 2030.
Those figures would exceed the country's Paris agreement commitment. The problem, though, is that Australia's targets are dramatically lower than many other major economies in the first place.
Australia has pledged to reduce its greenhouse gas emissions by 26% to 28% by 2030, from 2005 levels, a commitment dwarfed by those made by the United States, European Union and United Kingdom, among other developed nations.
US President Joe Biden, for example, increased his country's pledge in April to reduce emissions by 50% to 52% in the same time frame. The Australian Climate Council, which is independent of the government, has said a 75% slash in emissions would be more appropriate.
Morrison's bullish speech will have done little to boost Australia's standing at the conference. Despite being devastated by wildfires in 2019 and 2020, the country's government has concerned other developed nations with its rhetoric and moves on the climate crisis in recent weeks.
Delegates from smaller nations have expressed their disappointment with the action (or rather, lack of action) by the world's richest nations.
Mia Mottley, the Prime Minister of Barbados, an island that is already deeply threatened by rising sea levels, has warned that the climate crisis facing her country is perilous. She said it is a "code red to China, to the US, to Europe, to India."
Antigua and Barbuda's Prime Minister Gaston Browne told CNN he was "encouraged by the increased ambitions" set by world leaders at the COP26 summit, but he also expressed disappointment, saying the targets set don't go "far enough in order to contain rising global temperatures at 1.5 degrees Celsius."
And Panama's President Laurentino Cortizo said he is not feeling optimistic about what the COP26 conference can achieve.
"We've heard all of this before. What we need is an action," Cortizo said. "I am not optimistic there will be enough of it."
The COP26 President, British lawmaker Alok Sharma, said that being able to hold in-person negotiations, despite the ongoing Covid-19 pandemic, was a key goal of his presidency.
"For me it was vitally important that we have a physical meeting where every country is able to sit at the table, the biggest emitters, together with smaller nations, those who are the front line of climate change, and to be able to look each other in the eye as part of this negotiation," he told reporters on Sunday.
But keeping the event Covid-free has been a challenge.
All attendees have been asked to wear masks and take daily coronavirus tests. And while the venue is huge (approximately 1 kilometer from one end to the other), the sheer number of people on site makes social distancing difficult.
The UN Framework Convention on Climate Change, the body that is in charge of the negotiations, has admitted the pandemic is causing issues. For example, due to social distancing, the largest room reserved for negotiations can only hold 144 seats -- even though there are 193 parties to be represented at the conference.