Cows produce 5% of all global emissions, says the company.
A Welsh company planning to reduce carbon emissions by feeding garlic to cows has been highly commended at an awards ceremony.
Cardiff-based Mootral Ltd, which aims to reduce the amount of methane gas produced by cows, was recognised by the Carbon Trust Innovation Awards.
Tests have shown that the firm's food additive can achieve a 20% reduction.
Carbon Trust Wales manager Mike Batt said the awards "recognise the best innovative ideas to reduce emissions".
Each cow produces 500 litres of methane a day, equivalent to 10 tonnes of carbon dioxide a year, the firm explained.
In total, all cows worldwide produce more emissions than all cars and trucks combined, representing 5% of all global emissions.
Initial tests by the University of Aberystwyth and University of Reading have shown that the product, also called Mootral, can achieve a 20% reduction in methane emissions from the animals. The developers of the product hope to raise this to 50%.
Mootral co-founder Michael Mathres said the product was already in production and was ready to launch from Wales.
"The potential impact on carbon emissions is massive," he said.
"If Mootral was administered on a daily basis to every cow on earth, we could reduce carbon emissions by two billion tonnes each year."
The Carbon Trust Innovation Awards are judged by an independent panel of clean technology experts who assess each application on genuine innovation, carbon saving potential, novel application and commercial potential.
Mr Batt said: "These awards recognise the best innovative ideas to reduce carbon emissions and have a positive impact on climate change.
"We hope that this will inspire other Welsh companies to think innovatively about other ways to cut carbon emissions as we approach the next decade."