Duration

Two years

Motivation

• Under a global, low-carbon economy driven by hydrogen-based energy technologies, leakages at unprecedented scales are inevitable.

• Atmospheric H2 is largely controlled naturally by global soil sinks. The secondary H2 sink is reaction with atmospheric hydroxyl radical (OH).

• Soil micro-biotic & geophysical processes have nonlinear effects on H2 uptake controlled by temperature and moisture. These controls can weaken future soil H2 consumption under climate change.

• As global soil-sinks of H2 weaken, the H2 atmospheric-lifetime increases and its reactions with atmospheric OH are elevated.

• Resultant reductions in OH increase lifetimes and thus global warming by many powerful greenhouse gases (e.g. methane and HFCs).

Approach and Scope

• Projections and analyses with the Global Land System (GLS) within the MIT Integrated Global System Model (IGSM) to assess vulnerability of changes and weakening of the global soil uptake of H2 under possible future climate changes.

• Global 3D model (GEOS-Chem) projections of subsequent changes in global atmospheric OH and H2 from reduced soil uptake. Assess consequences for increases in powerful climate-forcing greenhouse gases whose main sink is OH.

Expected Takeaways

1. Determine the extent that human-forced climate change (in mean and variability) can impede the global soils’ uptake of atmospheric hydrogen.

2. Determine the OH-response consequences to increased atmospheric H2 (via reduced soil H2 uptake) on the concentrations, lifetimes and climate-forcing of powerful greenhouse gases whose main sink is OH.

3. Identify potential tipping points which could dramatically increase the climate impacts of hydrogen leakage.

4. Propose science-based actions regarding locations of global hydrogen production, limits on leakage, and needs for monitoring networks.