Causes: The many colours of hydrogen – fossil fuel scam
Causes
- A brief history of climate change: who knew what, when
- What causes climate change?
- Would the climate be warming without humans?
- Is it just a cycle? (Earth’s wobbly orbit)
- Sunspots & solar activity
- Land use: agriculture & cities
- Volcanoes
- Ocean currents
- Black carbon & ash
- Albedo effect
- Hydrogen
- Greenhouse gases & how they work
- – Carbon dioxide & the carbon cycle
- – Methane: biogenic (mostly cows) & ‘natural’ gas
- – Nitrous oxide (mostly agriculture)
- – Clouds & water vapour
- – Ozone
- – Man-made industrial chemicals
- – Aerosol pollution
- How to start an Ice Age!
- What’s in a name?
Other sections
Home > Climate wiki > What causes climate change? > Greenhouse gases > Blue hydrogen
Most hydrogen is a fossil fuel scam
Summary
Levels of hydrogen in the atmosphere have jumped by 60 per cent since pre-industrial times, underscoring the dramatic impact fossil fuel burning has had on the planet’s atmospheric composition. Although hydrogen is not a greenhouse gas, it has an indirect warming effect through reactions with other molecules. – New Scientist, Sept. 2025
Increasing levels of atmospheric hydrogen have led to “indirect” warming of 0.02C over the past decade. – Carbon Brief, Jan. 2026
Perhaps surprisingly, the greenhouse gas footprint of blue hydrogen is more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat. – Howarth et al, 2021
- Hydrogen (H) is the most abundant element in the universe; it makes up 70% of the sun and 90% of Jupiter. On Earth, it is present as a gas in the atmosphere only in tiny amounts – less than 1 part per million by volume. Any pure hydrogen (H) that enters the atmosphere quickly escapes the Earth’s gravity into space. It is nevertheless abundant when combined with other molecules, like oxygen, to form compounds like water (H2O) and carbon to produce methane (CH4). In some underground locations, due to the chemical interaction between certain rocks and groundwater, it can be found as gas.
- In its pure elemental form, hydrogen can be burned to generate energy. Because the only by-product is water, it’s a clean source of energy that does not contribute to climate change. However, to produce hydrogen requires separating it from other compounds through electrolysis, which creates the greenhouse gases carbon dioxide CO2 and methane CH4. Moreover:
- Blue hydrogen is a term invented by the fossil-fuel industry to greenwash dirty processes that release these greenhouse gases while claiming that some CO2 is captured and stored underground, with no evidence that it can’t escape (see Carbon Capture technologies this website).
- The ‘colours’ of hydrogen refer to the type of fuel used to create the energy needed to extract hydrogen through electrolysis:
- Blue: fossil fuel greenwashing to market black, brown, or grey hydrogen:
- Black: back coal
- Brown: lignite or brown coal
- Grey: methane
- Red or Pink: nuclear
- Green: any form of green energy: solar, wind, waves etc.
- Gold or White: hydrogen found in its natural state in underground reservoirs. However, energy will be needed to locate and mine hydrogen and some electrolysis may still be needed (link to page on this site).
- Blue: fossil fuel greenwashing to market black, brown, or grey hydrogen:
Causes
- A brief history of climate change: who knew what, when
- What causes climate change?
- Would the climate be warming without humans?
- Is it just a cycle? (Earth’s wobbly orbit)
- Sunspots & solar activity
- Land use: agriculture & cities
- Volcanoes
- Ocean currents
- Black carbon & ash
- Albedo effect
- Hydrogen
- Greenhouse gases & how they work
- – Carbon dioxide & the carbon cycle
- – Methane: biogenic (mostly cows) & ‘natural’ gas
- – Nitrous oxide (mostly agriculture)
- – Clouds & water vapour
- – Ozone
- – Man-made industrial chemicals
- – Aerosol pollution
- How to start an Ice Age!
- What’s in a name?
Other sections
Summary
Levels of hydrogen in the atmosphere have jumped by 60 per cent since pre-industrial times, underscoring the dramatic impact fossil fuel burning has had on the planet’s atmospheric composition. Although hydrogen is not a greenhouse gas, it has an indirect warming effect through reactions with other molecules. – New Scientist, Sept. 2025
Increasing levels of atmospheric hydrogen have led to “indirect” warming of 0.02C over the past decade. – Carbon Brief, Jan. 2026
Perhaps surprisingly, the greenhouse gas footprint of blue hydrogen is more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat. – Howarth et al, 2021
- Hydrogen (H) is the most abundant element in the universe; it makes up 70% of the sun and 90% of Jupiter. On Earth, it is present as a gas in the atmosphere only in tiny amounts – less than 1 part per million by volume. Any pure hydrogen (H) that enters the atmosphere quickly escapes the Earth’s gravity into space. It is nevertheless abundant when combined with other molecules, like oxygen, to form compounds like water (H2O) and carbon to produce methane (CH4). In some underground locations, due to the chemical interaction between certain rocks and groundwater, it can be found as gas.
- In its pure elemental form, hydrogen can be burned to generate energy. Because the only by-product is water, it’s a clean source of energy that does not contribute to climate change. However, to produce hydrogen requires separating it from other compounds through electrolysis, which creates the greenhouse gases carbon dioxide CO2 and methane CH4. Moreover:
- Blue hydrogen is a term invented by the fossil-fuel industry to greenwash dirty processes that release these greenhouse gases while claiming that some CO2 is captured and stored underground, with no evidence that it can’t escape (see Carbon Capture technologies this website).
- The ‘colours’ of hydrogen refer to the type of fuel used to create the energy needed to extract hydrogen through electrolysis:
- Blue: fossil fuel greenwashing to market black, brown, or grey hydrogen:
- Black: back coal
- Brown: lignite or brown coal
- Grey: methane
- Red or Pink: nuclear
- Green: any form of green energy: solar, wind, waves etc.
- Gold or White: hydrogen found in its natural state in underground reservoirs. However, energy will be needed to locate and mine hydrogen and some electrolysis may still be needed (link to page on this site).
- Blue: fossil fuel greenwashing to market black, brown, or grey hydrogen:
More information
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Video 2: While this explains electrolysis using green energy (to produce ‘Green’ hydrogen), fossil fuels are most commonly used as the energy source to create the electric current in electrolysis.
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- 2025: Ouyang et al; The Global hydrogen Budget, Nature article 17 December (Open access)
- Plain English: Hydrogen emissions are ‘supercharging’ the warming impact of methane, Carbon Brief
- 2025: Cuff; Atmospheric hydrogen is rising, which may be a problem for the climate, New Scientist 19 Sept.
- 2025: Zwaan et al; Rift-inversion orogens are potential hot spots for natural H2 generation, Science Advances 19 Feb 11|8
- 2024: Lyderson; Scientists Warn a Poorly Managed Hydrogen Rush Could Make Climate Change Worse, The Good Men Project
- 2022 Duan et al; Comment on “Climate consequences of hydrogen emissions” by Ocko and Hamburg (2022), Atmos. Chem. Phys. Discuss. [preprint] in review, 2022.
- 2021: Howarth et al; How green is blue hydrogen? Energy Science and Engineering 9 | 10 pp 1676-1687
- 2021: Baxter; Blue hydrogen; what is it, and should it replace natural gas? The Conversation
- 2021: IPCC Sixth Assessment Report; Climate Change 2021: The Physical Science
- 2025: Ouyang et al; The Global hydrogen Budget, Nature article 17 December (Open access)

