Offsets, generated through emission reductions such as planting trees or switching to less polluting fuels, currently trade in a voluntary market, often on a project-by-project basis with different standards and approaches.
The Voluntary Carbon Markets Integrity Initiative (VCMI) aims to ensure carbon offsets are underpinned by real actions to reduce greenhouse gas emissions and help developing countries access climate finance generated by the market.
It is sponsored by Britain and the philanthropic Children's Investment Fund Foundation, and has the backing of several governments including the United States.
"There are lots of people jumping into the voluntary market now without a broad consensus or agreement on assurance and integrity," VCMI co-chair Rachel Kyte said.
A task force created to scale up the voluntary carbon market has said the market will need to grow 15-fold to meet goals set under the Paris Agreement and could be worth as much as $50 billion by 2030.
The expected growth has led to an explosion of private sector interest, with trading houses setting up carbon desks and exchanges launching new voluntary carbon market products.
"We want to try to bring more and more countries and businesses into this conversation which tends to get dominated sometimes by the louder, shoutier voices in the global business community," said Kyte.
Other governments backing the scheme include Cambodia, Ghana, Kenya.
"We welcome the VCMI's focus on clear norms for companies to use high-quality carbon credits, including toward their net zero targets in a way that is credible, transparent, and aligned with the goal to limit global warming to 1.5 degrees," U.S. climate change envoy John Kerry said in a statement.
(Reporting By Susanna Twidale; Editing by Mike Harrison)
By Susanna Twidale