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CICERO-led study finds global warming effect of leaked hydrogen almost 12x stronger than CO2

A study led by Norwegian climate center CICERO has found that the global warming effect of leaked hydrogen is almost 12 times stronger than that of CO2. The open-access paper is published in Nature Communications Earth & Environment.

Unlike exhaust from burning coal and gas that contains CO2, burning hydrogen emits only water vapor and oxygen. Rather, it is the leaking of hydrogen from production, transportation and usage that adds to global warming.

Hydrogen is not a greenhouse gas, but its chemical reactions in the atmosphere affect greenhouse gases such as methane, ozone, and stratospheric water vapor. In this way, emissions of hydrogen can cause global warming, despite its lack of direct radiative properties.


The main changes in the radiative forcing due to 1 Tg flux of hydrogen; methane (green bars), ozone (yellow), stratospheric water vapor (purple), and aerosols (red). Sand et al.

The study was led by Dr Maria Sand, a senior scientist at CICERO, and her colleagues with collaborators from the UK, France, and the US, and was funded by the Research Council of Norway with contributions from five hydrogen industry partners.

The climate effects of hydrogen have been an under-researched topic. However, a few papers based on single model studies confirm our estimated global warming potential (GWP100) of 11.6.

We used five different atmospheric chemistry models and investigated changes in atmospheric methane, ozone and stratospheric water vapor. Hydrogen interacts with various biogeochemical processes. In our estimates, we have included soil uptake, photochemical production of hydrogen, the lifetimes of hydrogen and methane, and the interactions between hydrogen and methane.

—Dr Sand


The GWP100 of hydrogen. Sand et al.

The study is the most comprehensive assessment of the climate effect of hydrogen to date.

A global warming potential of 11.6 is significant, and our study clearly shows the importance of reducing hydrogen leaks. We lack the technology to monitor and detect hydrogen leaks at the scale needed, but new technology is being developed as the industry adapts.

—Dr Sand


  • Sand, M., Skeie, R.B., Sandstad, M. et al. (2023) “A multi-model assessment of the Global Warming Potential of hydrogen.” Commun Earth Environ 4, 203 doi: 10.1038/s43247-023-00857-8



Hopefully another nail in the H2 coffin.
+ you can expect a fair few H2 leaks as the molecule is very small and H2 causes H2 embrittlement.
Never simple, is it.


The trick is to transform the hydrogen into methanol so it is less prone to leak and is more practical. It is time for cemvita to start expanding.


Where does the energy come from to transform to methanol? If you say wind and solar, you are taking those out of direct production of electricity.


Time to get serious about geothermal.



Most hydrogen due to be produced is from areas with very favorable wind and solar resources such as Morocco and the Arabian gulf, where there is little question the direct production of electricity as an alternative, so it is not either/or.

William Taylor

Just make the system leakproof. It is doable. And use SMR’s as generation.



From the provided link to the source paper:

' Our estimated GWP100 of hydrogen is 39% of that to fossil fuel methane GWP100 in AR633.'

So methane at least is over twice as powerful as hydrogen over a 100 year period.

Just about any energy source is going to impact climate, the question is how much.

Sure, hydrogen is over 11 times as potent a source of warming as CO2 per kg over a 100 year period, but present energy production relies on burning fossil fuels, with all of it going into the atmostphere.

For hydrogen, it is not inherent in its production and use, but only in whatever proportion escapes.


To illustrate why this is not the show stopper a casual glance might imply, although a serious issue requiring attention, just about the area of the world where it is most difficult to use electricity directly due to its high latitude is Europe.

But even there hydrogen is expected to only provide 20% of total power by 2050:


Note the 10% globally.

And for current and projected leakage rates:

' A high-risk scenario based on hydrogen demand from the International Energy Agency (IEA) net-zero scenario (528 million tons [Mt] by 2050) (IEA 2021) could potentially lead to a 5.6 percent economy-wide leakage rate, compared with an estimated 2.7 percent in 2020.'


So roughing out some figures for the world:

10% of world energy production from hydrogen, with a leakage rate of ~5%
comes out to 0.5% per total kwh of energy consumed in 2050

Times ~10 for the extra potency of hydrogen against CO2 comes to 10% per kwh against generating power purely by combustion.

I've played fast and lose with lots of stuff there, including the differences in CO2 emissions of different fossil fuels and that total energy consumed will be way more in 2050 than now, but I am hoping to simply indicate that it is only envisaged that a relatively low proportion of total energy consumption will use a hydrogen path, and that there are a host of mitigation strategies, so in spite of the GWH potential of hydrogen it would appear that we can make very good progress


Methane is 60 times more potent than CO2
we release vast quantities of it compared to hydrogen
we should concentrate on real issues.


As a hydrogen advocate, it behoves me to say when a real issue is raised, which this is.
What it ain't though is a show stopper.

Of course you take you electricity 'straight' when it is practical.

The thing is, it often isn't, which is all I have ever claimed.


I have a definite preference for storing surplus electric energy in a manner that has a low environmental impact, is cheap and safe, has high energy density, is fast charging and has a long cycle life as compared against H2(Methane) with all its negative attributes..


Batteries are practical and economic for short term storage, of the order of 4 hours.

They are anything but for long term storage, which is why in practice they are not used that way.

The costs for, say, seasonal storage, would be astronomic, which is why no one at all is using them that way.

Thomas Pedersen

A 'per-kilogram' comparison is the least favorable you could possibly make for hydrogen.

Each kg of hydrogen used instead of CH4, saves 6.6 kg of CO2 directly. So if you loose 1% of the hydrogen, due to leakages you would not have with natural gas, you still come out 55 times better, equating to a 98.2% GWP reduction. But that's a completely different headline and conclusion than "Hydrogen has 12 times more GWP than CO2".

My nose detects a hint of "nothing is good enough. Nothing technical can work. The only thing we can do is panic or dissemble the modern, capitalist society."

I realize that's a bit of a stretch. But I have notice in my quarter century within the energy sector, and working with both carbon capture, hydrogen production, methanol synthesis, etc. that there are always objections in the direction of 'Nothing, except our ideologically determined solutions, can work'

Roger Pham

The mechanism for the alarmist here appears to be that escaping Hydrogen mops up hydroxyl ions in the lower atmosphere. The Hydroxyl ions are responsible for breaking down methane, and without them more methane stays in the atmosphere with 10X the warming effect of CO2.

However, this study is very short-sighted in its assumption that the methane emission rate will remain the same in the future...Quite the contrary, once the world will use H2 to replace methane (in natural gas), there will no longer be methane leakage cause by human consumption, so the rate of methane emission into the air will dwindle.

H2 is not a greenhouse gas by itself, so replacing methane with H2 will significantly reduce the amount of green house gas in the atmosphere and will be of great benefit to reduce global warming.

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