LONDON - Five of the world's largest carbon credit programmes have now been given initial approval by a body tasked with raising standards in the market for carbon offsets, where some of the biggest buyers include Microsoft, Salesforce and Amazon.

Integrity Council for Voluntary Carbon Markets (ICVCM) has added Verra and Architecture for REDD+ Transactions (ART) to its list which meet its Core-Carbon Principles rule book.

Allowing companies to buy credits from projects that lock carbon away, such as mangrove restoration, and use them to offset their emissions is seen as an important way to help developing countries protect the environment.

But growth has been held back by challenges including concerns over the origination, credibility and efficacy of certain credits, and the claims made about buying them.

ICVCM, which is backed by Bezos Earth Fund and Children's Investment Fund Foundation, is working to address these.

Pedro Barata, co-chair of the expert panel for ICVCM told Reuters that its standards make a compelling case that companies can invest in "high quality" carbon credits, without needing to worry about accusations of so-called greenwashing.

Adding Verra and ART to ICVCM's approved list, which includes ACR, CAR and Gold Standard, means its governance and transparency standards now cover programmes which have a 98% share of the market, based on carbon credits retired in 2023.

It marks the first step in a process that will see Core Carbon Principle-labelled credits issued in the market and comes as part of efforts to scale-up the voluntary market for buying and selling carbon offsets by setting rules for what high quality credits and appropriate offsetting activities look like.

ICVCM's next step is its ongoing assessment of the different methodologies carbon crediting programmes use to produce credits which range from afforestation to cooking stoves.

It is working through 100 such methodologies and expects to announce its first decisions in June.

(Reporting by Virginia Furness; Editing by Alexander Smith)