The Overlooked Role of Hydrogen in Climate Change

Recent research published in *Nature* by the Global Carbon Project reveals that increasing hydrogen emissions have contributed to global warming and exacerbated the effects of methane, a potent greenhouse gas. The study indicates that atmospheric hydrogen levels rose from 523 parts per billion (ppb) in 1992 to 543 ppb in 2020, leading to an estimated indirect warming of 0.02 degrees Celsius from 2010 to 2020. This warming effect, while seemingly small, is comparable to the emissions impact of an industrialized nation like France.

Carbon BriefOverlooked hydrogen emissions are heating Earth and supercharging methaneThe Straits Times

Hydrogen itself does not trap heat in the atmosphere; however, it interacts with hydroxyl radicals, which are crucial for breaking down methane. As hydrogen levels rise, these "detergents" become less available to react with methane, allowing it to persist longer in the atmosphere and contribute to further warming. The study's lead author, Zutao Ouyang, emphasizes that the primary source of atmospheric hydrogen is the oxidation of methane, which has been increasing due to human activities such as fossil fuel extraction, agriculture, and waste management.

Overlooked hydrogen emissions are heating Earth and supercharging methaneCarbon Brief

The study identifies that 56% of atmospheric hydrogen emissions from 2010 to 2020 originated from the oxidation of methane and non-methane volatile organic compounds (NMVOCs). Other significant sources include leakage from industrial hydrogen production and nitrogen fixation processes in agriculture. Notably, while human-induced sources of hydrogen have increased, natural sources have remained stable over time.

Carbon BriefOverlooked hydrogen emissions are heating Earth and supercharging methane

As the world transitions to a hydrogen economy, understanding the hydrogen cycle's role in climate change is crucial. Currently, over 90% of hydrogen is produced through carbon-intensive methods, such as steam methane reforming. The potential for "green hydrogen," produced via electrolysis using renewable energy, exists but faces economic and logistical challenges. Rob Jackson, a senior author of the study, warns that without addressing leakage and methane emissions, the benefits of hydrogen as a clean alternative to fossil fuels may be undermined.

Carbon BriefOverlooked hydrogen emissions are heating Earth and supercharging methane

Experts have noted that the study provides a much-needed assessment of the global hydrogen budget, highlighting the necessity for a deeper understanding of hydrogen's climate impact. Critics argue that while hydrogen holds promise for decarbonization, its current production methods and associated emissions must be critically evaluated to avoid exacerbating climate issues.

Carbon Brief

• “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.” — Rob Jackson, Stanford University

Overlooked hydrogen emissions are heating Earth and supercharging methane

• “More hydrogen means fewer detergents in the atmosphere, causing methane to persist longer and, therefore, warm the climate longer,” — Zutao Ouyang, Auburn University

Overlooked hydrogen emissions are heating Earth and supercharging methane

• “We need a deeper understanding of the global hydrogen cycle and its links to global warming to support a climate-safe and sustainable hydrogen economy,” — Rob Jackson, Stanford University

Overlooked hydrogen emissions are heating Earth and supercharging methane

The findings from the Global Carbon Project underscore the complex interplay between hydrogen and methane in the context of climate change. As hydrogen emerges as a potential cornerstone of future energy systems, addressing its emissions and understanding its environmental impact will be critical for achieving climate goals.

The Straits Times