Forty five nations signed on to a pledge to protect natural environments and combat emissions from agriculture during the 26th United Nations Climate Change Conference of the Parties, or COP26, in Glasgow, Scotland, on Saturday, as tens of thousands joined climate change demonstrations across the city.

On a day dedicated to nature and land use, the United Kingdom government said in a statement fellow signatories had "pledged urgent action and investment to protect nature and shift to more sustainable ways of farming".

The UK said participating nations leveraged $4 billion of new public sector investment into agricultural innovation.

"If we are to limit global warming and keep the goal of 1.5C alive, then the world needs to use land sustainably and put protection and restoration of nature at the heart of all we do," COP26 President Alok Sharma said on Saturday.

Agriculture, forestry and land use is responsible for around 25 percent of global greenhouse gas emissions, and the UK Environment Department said there is an "urgent need to reform the way we grow and consume food in order to tackle climate change".

"The commitments being made today show that nature and land use is being recognized as essential to meeting the Paris Agreement goals, and will contribute to addressing the twin crises of climate change and biodiversity loss," said Sharma.

On Saturday, 160 stakeholders including government and agriculture companies joined the Global Agenda for Innovation in Agriculture, which the UK said will "lead the way" on the global transition towards climate resilient agriculture and food systems to more sustainable ways of farming.

Environment Secretary George Eustice said that, in order to meet the goals of the Paris Agreement, "we need action from every part of society, including an urgent transformation in the way we manage ecosystems and grow, produce and consume food on a global scale".

Meanwhile, thousands of demonstrators gathered in Glasgow and in cities across the UK to bring attention to climate issues. Organizers, including the COP26 Coalition, said that an estimated 100,000 people marched in Glasgow alone for the Global Day of Action on Saturday.

"I wouldn't be anywhere else on the planet but here right now, to speak out about the climate emergency," Bors Hulesch, a speaker for environmental activism group Extinction Rebellion, told China Daily. "My message to delegates at COP26 is I need to hear about leaving fossil fuels in the ground, I need to hear about stopping new fossil fuel investments."

A good natured throng of demonstrators marched for about 4 kilometers, from Kelvingrove Park to Glasgow Green in the city center, on an unpredictable day punctuated with heavy showers and short periods of sunshine.

Students and academics were joined by trade unionists and campaign groups, along with numerous families and banner-bearing climate activists.

Swedish climate activist Greta Thunberg was initially scheduled to deliver a speech, though she cancelled in order to share the spotlight with other campaigners, according to organizers.

"The climate and ecological crises are already here. But so are citizens from around the globe," Ugandan environmental advocate Vanessa Nakate told the crowd in Glasgow. "It takes citizens, people like you and me, to rise up and demand action. And when we do that in great enough numbers, our leaders will move."