Solar Radiation Management: FISOC: Framework for Ice Sheet

FISOC: Framework for Ice Sheet – Ocean Coupling

ESMF regridding options include unstructed meshes

ESMF example grids

Elmer/Ice example mesh

Solar Radiation Management: Potential, Risks and Outlook

J.C. Moore

Conserving the Planet

地球工程机理示意图

Royal Society Report, 2009

John Sheperd

Ocean chemistry projection using a coupled climate-carbon cycle model

0 1 2 3 4

Saturation state of calcium carbonate

(Ωaragonite)More acidic

5

Cao and Caldeira, 2008

Less acidic

Climate change is felt differently in the developing world• Impacts are already happening

• For some it is already an existential threat

• Many have a far different view of man and nature than the Western one

• Surveys show they are more open to any solution –they know man caused this problem, they hope man can fix it

Tropical circulation: Hadley cell

Guo et al., 2018

Changes under SRM

Changes under GHG

Tropical circulation: Walker cell

Guo et al., 2018

Tropical circulation: Walker cell

Guo et al., 2018

Changes under SRM

Changes under GHG

Hincket et al., PNAS 2016

21st century Global sea level rise will affect hundreds of millions of people on our planet. World Bank, 2007

- 500 million people for 1 m rise (USGS)

Flooding due to rising global sea level

Cost of 1.8 m coastal flooding as a 95% limit, (Jevrejava 2016) = €50 trillion/year by 2100Coastal protection cost =€15-70 billion/year (Hinckel 2014)

Antarctic Mass Loss

Pritchard et al., 2009

The soft underbelly of Antarctica

The future

The Greenland ice sheet is expected lose at least 90%

of its current volume if ice sheet summer temperatures

warm by around 1.8C above pre-industrial

Why is happening?

Warming temperatures

Air and ocean in Greenland

Ocean warming in Antarctica

PLUS Inherent instability of parts of the ice sheet

Risks from SRM

Changes from present climate- All simulations show much smaller

changes under SRM than under greenhouse gas forcing alone.

Because most changes depend on changes in temperatures – even precipitation patterns.

Risks from SRM

Changes due to new processes- SRM by aerosol injection would create new

chemistry in the stratosphere. We know bad things happened with ozone due to CFCs in 1980s

Would similar things happen again?Climate models were much cruder in 1980s than now. But there is a lack of physics knowledge about aerosols in the stratosphere

Risks from SRM

Moral hazard- Would SRM provide an opportunity to

neglect mitigation?

Evidence is mixed – reverse moral hazard may also exist

Risks from SRM

Governance- How to decide what level intervention to

make?

As an engineering problem we could decide sophisticated global temperature regimes –matching much of present day variations (N-S, equator-Pole, mean T)Would states agree on an optimum temperature? – to preserve the cryosphere they would have to

What could SRM achieve?

Huge injections needed to offset RCP8.5

Tilmes et al BAMS 2018

What could SRM achieve?

More likely limited to 1-2C decreases

To avoid overshoot it would need to be done for 150 years

Need an exit strategy

John Sheperd

Can anything else be done?

• In some cases Targeted Geoengineering might provide partial solutions

• Pleistocene Park in Siberia for permafrost

• Ice911 for sea ice

• Glacier geoengineering for sea level

Is it scientific?

Ethical obligation: Egalitarian &Transgenerational

Failsafe