More than 100 world leaders have promised to end and reverse deforestation by 2030, in the COP26 climate summit's first major agreement. Brazil – where huge swathes of the Amazon rainforest have been cut down – was among the signatories on 2 November. The pledge includes almost £14bn ($19.2bn) of public and private funds.

The countries that have signed the pledge – including Canada, Brazil, Russia, China, Indonesia, the Democratic Republic of the Congo, the US and the UK – cover around 85% of the world's forests. Some of the funding will go to developing countries to restore damaged land, tackle wildfires and support indigenous communities. Governments of 28 countries also committed to remove deforestation from the global trade in food and other agricultural products such as palm oil, soya and cocoa. These industries drive forest loss by cutting down trees to make space for animals to graze or crops to grow.

More than 30 of the world's biggest financial companies – including Aviva, Schroders and Axa – have also promised to end investment in activities linked to deforestation. And a £1.1bn fund will be created to protect the world's second largest tropical rainforest, the Congo Basin.

Experts have welcomed the move, encouraged by the scale of participation by key countries and the scale of funding, and by the prospect of strengthening the ability of indigenous people to protect their forest habitats, but there are significant challenges.

Many previous plans haven't achieved their goals. In fact, deforestation has increased since a similar pledge was launched in 2014. And there are questions over how a major financial commitment could be effectively policed. How can funders verify that forests are actually being protected without, for example, spying from satellites? And it may be very problematic to remove the link to deforestation from consumer goods sold in developed countries, in particular meat supplied by farming animals that graze on pastures created by clearing forests.