Understanding Earth’s Greenhouse

Robert D. Cormia

Foothill College

Overview and Goals

• What keeps earth warm?

• How does the Greenhouse work?

• What does Vostok tell us?

• Fossil fuel emissions and GHGs

• Current and future forcing, feedbacks

• What you can do be being smarter

Black Body Radiation

http://en.wikipedia.org/wiki/Black-body_radiation

The Greenhouse Effect

An overview of the Greenhouse Effect. From IPPC Working Group 1 contribution, Science of Climate Change, Second Assessment Report 1996

Greenhouse Gasses (GHGs)

• CO2

• CH4

• H2O

Methane – CH4

Carbon dioxide – CO2

Carbon Dioxide

CO2 is the Greenhouse Gas that we follow the most as fossil fuels contribute to it directly. CO2 also absorbs energy near 700 nm. A doubling of CO2 would raise earth’s temperature by nearly 3 degrees Celsius.

Methane

• Potent GHG – 20x CO2 / mole

• 10 year half-life

• -OH combination

• Agriculture plus mining/fracking

• Sleeping giant (permafrost)

Water Vapor

• Water vapor is actually the most potent GHG (by contribution)

• Reacts to changes in surface temperature

• Key in feedbacks

Ice Cores – Story of Vostok

Vostok Ice Core Data•A perfect correlation between CO2, temperature, and sea level•For every one ppm CO2, sea level rises 1 meter, temp rises .05 C (global)•Process takes 100 years to add 1 ppm CO2, and reach thermal equilibrium

This is not just a correlation, this is a complex and dynamic process, with multiple inputs. Touching one input affects all other inputs, and increases in temperature becomes a further feedback and multiplier of these inputs.

GHGs and Vostok Data

James Kirchner Department of Earth and Planetary Science, University of California, Berkeley

Global Carbon Cycle

The Thermostat Inputs

• CO2 - largest input

• CH4 – most potent input

• Water vapor – potent GHG• Clouds – absorb / reflect• Albedo – moderates energy• Temperature

– Reacts to increased forcings– Amplifies / induces other inputs

Earth’s Biogeochemical Thermostat (Cormia) Missing Feedbacks (Torn, Harte)

Dials on the Thermostat

CO2

CH4

Ice / albedo

Water vaporClouds

Temperature

GHGs force energy into the planet, surface warming leads to feedbacks

Thermal inertiaClimate feedbacksGHGs

250 yrs of Carbon Emissions

It took 125 years to burn the first trillion barrels of oil – we’llburn the next trillion in less than 30 years – why should you care?

http://en.wikipedia.org/wiki/Keeling_Curve

Keeling Curve CO2

http://www.esrl.noaa.gov/gmd/ccgg/trends/

Carbon Emissions and CO2

• Carbon burned => CO2

• Linear from 1850 to 2000- ppm CO2 =2.55 e10-4 *M tons C +

297 (r2*100=99.6%)

• ~ 50% of carbon goes into atmospheric CO2

– 50% oceans / soil

• Trend is constant over 100 years – is this how the biosphere will react over the next 500 years?

Year C burned ppm CO2

1900 12307 2951910 19174 3001920 28050 3051930 37914 3101940 48566 3101950 62324 3151960 83453 3201970 115935 3251980 164083 3401990 219365 3502000 283373 3702010 365000 390

Projected Energy Demand

Future CO2 – the Next 15 Yrs

Year Emissions CO2

2000 283,373 369

2005 318,465 378

2010 357,209 388

2015 399,986 399

2020 447,216 411

2025 499,360 424

2030 556,932 439

Earth Out of Balance

http://www.giss.nasa.gov/research/news/20050428/

Earth’s Energy Imbalance

Emission Trajectories

• We are adding 2+ ppm CO2 to the atmosphere every year, and is increasing

• China passed US in GHGs emissions 5 years ago, and is now nearly double US

• Oil and hydrocarbons are actually plentiful• Coal is still setting production records • Population, wealth, and consumption

CO2 Trajectories to 2oC

http://www.pik-potsdam.de/news/press-releases/files/synthesis-report-web.pdf

Don’t have 20 years to Wait

• Trajectory to 450 ppm CO2 (2032-2035)

– 450 ppm CO2 => 2 deg C committed/forcing

– Amplifying feedbacks take us to 3+ deg C

• Ocean acidity 450 ppm CO2 => pH 8

– concentration [CO2] = [HCO3]

• Decisions made today impact 2035– Still investing in carbon intensive energy

– At 2+ ppm/year, for 20+ years, 450 ppm CO2

Heat Storms in the US

Record heat across the US in summer, including an oppressive heat index

Superstorm Sandi 2012

www.theatlantic.com

Greenland Ice Melt

Glaciers and Ices Sheets in the Arctic - http://www.eoearth.org/view/article/152985/

Ocean Acidification

http://www.pmel.noaa.gov/co2/story/Ocean+Acidification

Ocean Acidification

CO2 dissolves in water to produce mild carbonic acid, which dissociates into bicarbonate and carbonate ion. Increasing acidity removes carbonate ion from solution. At pH 8 (450 ppm CO2)

carbonate ion is under-saturated, shells will be difficult to form and stay stable.http://www.ocean-acidification.net/FAQacidity.html

Arctic Sea Open Ice in 2015

http://arctic-news.blogspot.com/2012/11/arctic-sea-ice-set-to-collapse-in-2015.html

Methane Hydrates

http://www.wwfblogs.org/climate/content/methane-arctic-seafloor-mar2010

What you can do…

• Understand earth’s greenhouse process

• Decide if you want to make a difference

• Measure your carbon footprint!

• Develop your own climate action plan

• Talk to people about what you know

Summary

• Science isn’t holding us back

• Our collective behaviors are

• Technology isn’t (all) the answer

• Efficiency and energy intensity

• Making better carbon decisions

References/Attribution• Climate Change Index -

http://www.igbp.net/4.56b5e28e137d8d8c09380002241.html

• 350.org• CO2now.org • EIA – http://www.eia.gov• NOAA Climate Center• https://www.ncdc.noaa.gov/sotc/global/2011/13 • http://www.esrl.noaa.gov/gmd/ccgg/trends/

• Skeptical Science - https://www.skepticalscience.com/

• International Arctic Research Center • http://www.iarc.uaf.edu/

This presentation is intended solely for use/remix for educational purposes