Nineteen prominent leaders from conservation, science, finance and business have written an open letter to the International Sustainability Standards Board, urging it to develop a dedicated standard on nature. The letter was published on 20 April 2026, two days before the ISSB Board meeting scheduled for Earth Day, 22 April.

The signatories say they are "extremely concerned" by reports that ISSB staff have recommended against developing a nature standard. They describe this as a decision that would disregard the latest science, growing private sector momentum and global policy commitments. In their words, they call it "a regressive decision that would delay progress."

The letter is addressed to ISSB Chair Emmanuel Faber and Board Members, and carries signatures from figures including Kirsten Schuijt of WWF International, Jennifer Morris of The Nature Conservancy, Sebastian Troëng of Conservation International, Eva Zabey of Business for Nature, Johan Rockström of the Potsdam Institute for Climate Impact Research, and Paul Polman, among others.

 

Why nature cannot be separated from climate

 

The signatories stress that the science is clear on the need to integrate nature and climate action. They point out that reducing emissions without also protecting natural carbon stocks and sinks will prevent the world from achieving the Paris Agreement goal of limiting warming to 1.5°C. For businesses and financial institutions, they argue, this means that nature must be part of decision-making. Otherwise, the financial impacts of climate change, which the ISSB's existing standards already address, cannot be properly assessed.

They go further: even if all climate targets on greenhouse gas emissions were met, the current pace of nature loss would on its own push us beyond the Paris climate limit. Nature, they write, "regulates the ultimate stability and resilience of all biosphere functions that form the basis for the global economy."

The letter cites the World Economic Forum's 2026 Global Risks Report, which placed extreme weather events, biodiversity loss and ecosystem collapse, and critical changes to Earth systems at the top of its list. It also references the IPBES Business and Biodiversity Report, which found that biodiversity losses caused by economic activity put the future of businesses, the economy and global society at risk. Research from Oxford University, Global Canopy and TNFD, issued in 2025, highlighted 600 examples of nature-related financial materiality.

According to the World Bank, global potential costs from nature loss could reach up to $2.7 trillion per year. Nature loss, the signatories say, directly affects food security, water availability and economic stability, which makes it financially material.

 

Growing recognition across business and finance

 

The letter highlights the accelerating recognition of nature-related financial materiality across the private sector and regulatory landscape. It points to the EU's ESRS E4 Standard on Biodiversity and Ecosystems, new GRI and ISO biodiversity standards, the 750 early adopters of the TNFD framework, more than 500 stakeholders engaged through the Nature Positive Initiative in developing practical metrics for measuring the state of nature, and the over 200 financial institution signatories of the Finance for Biodiversity Pledge.

The signatories also note that measuring nature is becoming increasingly practical, thanks to the standardisation of metrics, granular Earth observation data, innovations such as environmental DNA, open access data platforms, and the ability of AI to synthesise this information.

Investors, they argue, require standardised and comprehensive nature disclosures from companies to make informed capital allocation decisions. The news that ISSB would develop a nature standard had been positively received by many financial institutions, which makes the reported change in direction all the more concerning.

 

The case for a standalone S3 standard

 

Rather than folding nature into existing frameworks in a non-mandatory way, the signatories call for a standalone nature standard, effectively an S3, that draws on the TNFD's guidance and is designed to integrate with the ISSB's existing S1 and S2 standards. They argue this approach would minimise disruption to the ongoing adoption of S1 and S2 by countries, while filling what they describe as a significant gap around assessing financially material nature-related impacts and dependencies.

They also make a governance argument. Under the Kunming-Montreal Global Biodiversity Framework, 196 governments have committed to introducing mandatory requirements for reporting on biodiversity through Target 15. A dedicated ISSB nature standard would provide a unified international framework for countries to implement this target, lifting what the signatories describe as a significant implementation burden from many of these nations.

The letter notes that a dedicated S3 nature standard was also recommended to the ISSB Board by the majority of the 16 regulator members of the IFRS Sustainability Standards Advisory Forum at their meeting on 24 March 2026.

 

An Earth Day decision

 

The signatories draw attention to the symbolism of the timing. The ISSB Board meeting falls on Earth Day, a day they describe as an occasion to signal global unity for environmental protection and a shift from awareness to active stewardship.

They close by calling on the ISSB to agree to develop a nature standard that would support and enable the private sector to assess and address their nature impacts and dependencies, in the interests of business resilience and societal health.

Should the Board choose to follow the staff recommendation for a non-mandatory approach, the signatories warn this would be clearly out of sync with today's science, financial materiality, momentum and needs.

The decision now sits with the ISSB Board.

 

Link to the open letter - here