New research published in the journal Nature shows that atmospheric hydrogen has contributed about 0,02°C to global warming since the industrial revolution, highlighting its indirect role in climate change. The research emphasises the need to limit leaks from future hydrogen fuel projects and to reduce methane emissions if hydrogen is to realise its potential as a clean-burning energy source.
The research paper, titled “The global hydrogen budget”, estimates that annual hydrogen emissions have increased by roughly four million tonnes since 1990, reaching about 27 million tonnes a year by 2020.
“The best way to reduce warming from hydrogen is to avoid leaks and reduce emissions of methane, which breaks down into hydrogen in the atmosphere,” said Stanford University scientist Rob Jackson.
According to the researchers, hydrogen does not directly trap heat in the atmosphere unlike carbon dioxide and methane. However, it indirectly contributes to warming by interacting with other gases and consuming natural atmospheric “detergents” that would otherwise help break down methane.
“More hydrogen means fewer detergents in the atmosphere, causing methane to persist longer and therefore warm the climate for longer,” said Lead Author and Assistant Professor at Auburn University, Zutao Ouyang.
The study notes that soils have removed about 70% of hydrogen emissions since 1990, mainly through bacterial activity. Hydrogen reactions can also produce ozone and stratospheric water vapour and may influence cloud formation.
The researchers reiterate that hydrogen produced via electrolysis using renewable energy can be generated and used with near-zero carbon emissions, supporting projections for substantial growth in hydrogen use this century.
