Methane hydrates: Impact on nature
A climate-sensitive carbon store, and seabed risks
What this tab covers What taking energy from this source does to land, water, air and climate, wildlife and ecosystems, with life-cycle emissions and land use where measured.Hydrates matter to nature mainly as a large, climate-sensitive store of carbon. Producing them would add the usual impacts of offshore gas, plus risks of uncontrolled dissociation, sea-floor instability and leaks.
Life-cycle emissions about 202 (combustion only) g CO2/kWh of fuel heat11 Converted from the IPCC default for natural gas (56.1 t CO2/TJ). No life-cycle assessment of commercial hydrate production exists, because there is none. Upstream energy use and leaks would add to this.Effects on nature
| Area | Effect | Size | How it is reduced |
|---|---|---|---|
| Climate (carbon store) | Hydrates hold a large share of the carbon that can move between Earth's reservoirs.10 | About 1,600 Gt of carbon, up to 25% of the mobile carbon budget of the earth, ocean and atmosphere | Not applicable; the main safeguard is limiting ocean warming |
| Climate (natural release) | No conclusive proof that hydrate-derived methane is reaching the atmosphere now. Most is oxidised in sediments and seawater.4 | About 1% of global methane emissions (5 to 6 Tg CH4 per year) | Monitoring of seeps and bottom-water temperatures |
| Climate (combustion) | Produced hydrate gas is methane and burns like natural gas.11 | 56.1 t CO2/TJ, the same as natural gas | Use with CCS; strict leak control because methane is a strong greenhouse gas |
| Sea floor and seeps | Methane escapes naturally from margins where hydrate lies. Production could add new leakage paths and weaken sediments.2 | More than 570 gas plumes from sea-floor seeps found in 94,000 square km of the US Atlantic margin | Site surveys, sea-floor monitoring, slow and controlled depressurisation |
| Water | Dissociation releases large volumes of water with the gas, which must be lifted and disposed of.9 | About 1,250 cubic metres of water alongside 119,500 cubic metres of gas in the 6-day 2013 Nankai test | Downhole separation, reinjection or treatment |
The fear that warming could trigger a sudden, massive hydrate methane release is not supported by current evidence. USGS researchers concluded that breakdown of gas hydrates is unlikely to cause one, mainly because most deposits are deep and the released methane is largely consumed before it reaches the air. The risk is a slow, long-term addition, centred on upper slopes and Arctic shelves.
Production would leave a footprint similar to deep-water gas, with extra concerns about sediment strength and sand inflow, because the hydrate itself holds the sediment together.
Sources
- U.S. Geological Survey Gas Hydrates Project (project page, page 2) USGS Woods Hole Coastal and Marine Science Center, 2024
- The interaction of climate change and methane hydrates (Ruppel and Kessler), Reviews of Geophysics 55 American Geophysical Union, 2017
- Gas hydrate energy research: 2024 update USGS, 2024
- Frozen Heat: new international report on methane hydrates USGS, 2014
- 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Vol. 2 Energy, Ch. 1 Introduction (Tables 1.2 and 1.4) IPCC, 2006