LONDON - The number of fossil fuel companies setting net-zero emissions targets has risen sharply over the past year but most fail to address key concerns, making them "largely meaningless," a report showed on Monday.

Some 75 of the world's largest 112 fossil fuel companies have now committed to reaching net-zero — the point at which greenhouse gas emissions are negated by deep cuts in output elsewhere and methods to absorb atmospheric carbon dioxide.

That's up from just 51 a year ago, according to the assessment of publicly available data by Net Zero Tracker, run in part by the Britain-based Energy and Climate Intelligence Unit and the University of Oxford.

But most targets do not fully cover or lack transparency on Scope 3 emissions — which include the use of a company's products, the biggest source of emissions for fossil fuel companies — or don't include short-term reduction plans, the report added.

READ MORE: How much are fossil fuel companies to blame for western wildfires?

The report also found that none of the fossil fuel companies were making the needed commitments to move away from fossil fuel extraction or production.

As it stands, some 4,000 countries, states, regions, cities, and companies globally have now committed to net-zero. Last November, the UN issued guidance on what a "good" net-zero strategy should look like to avoid greenwashing.

"We haven't yet seen a huge move from fossil fuel companies or other companies on meeting those (guidelines), so there's still a lot of work to do to come up to that level," said Thomas Hale of the University of Oxford, who co-authored the report.

Daisy Streatfield, sustainability director at global asset manager Ninety One, said "credible plans and meaningful execution are not going to happen overnight," with many companies doing a better job than national governments.

A study published last week in the journal Science found that about 90 per cent of countries' net-zero targets were unlikely to be achieved.

Reporting by Gloria Dickie and Simon Jessop in London; editing by Jan Harvey.

Thumbnail image: The Houston Ship Channel and adjacent refineries, part of the Port of Houston, are seen in Houston, Texas, U.S., May 5, 2019. (REUTERS/Loren Elliott)