Global Warming What is it? What’s causing it? What are the solutions?

Greenhouse effect

CO2: one of the main heat- trapping gases. Its concentration in the atmosphere, past 250 yrs. Past 10,000 yrs

CO2 concentration: 400,000 yrs--4 ice ages. Read graph from right to left. Recent increase unprecedented, NOT a natural cycle. Present interglacial period

2010, 2005, 1998: tied as hottest years on record : hottest decade on record. It’s getting warmer

Global warming is here now! The number of severe hurricanes has increased by 80% during past 30 yrs. Droughts in Texas, western states. Decrease in migratory birds, due to warmer winters in northern states. Increase in tree mortality, Western U.S. pH of ocean is dropping due to CO2; affects corals, shellfish. Range shifts of MANY biological species. Forest fires are increasing, as predicted. Prolonged dry spells. Reduced snowpack. More rain, more extreme rain. Polar bear now “endangered.” Bacterial “blooms” in waters. ETC!

Glacier nat park, Montanna-1 Glacier National Park, Montana, is melting. 1850: 150 named glaciers. 2007: : 0 expected

S Cascade Glacier, Washington, 1928, 1979, 2003.

Alaska

Austria

Arctic melt extent, 1979 and 2003 Expected to be ice-free in summer by Recentlly: Melting has accelerated. “Arctic ice could be in an abrupt, irreversible decline.” Are we approaching a tipping point? Reflectivity feedback could have serious consequences for Greenland.

Greenland ice is melting

Greenland melt extent

James Hansen, NASA’s chief climatologist, GW expert: Earth could pass a “tipping point” during next 10 to 20 yrs that would initiate irreversible melting of the Greenland and W Antarctic ice caps, raising sea levels by 50 feet over the next few centuries and “produce a new planet.” We could see 10-ft rises by the end of this century.

Is this what you want for your grandchildren? It’s a moral issue!

What’s causing the warming? When we look at the patterns of global changes (temps, ice, rainfall, etc.) …..

…we find that natural sources cannot explain it, but human-emissions of greenhouse gases do. Intergovernmental Panel on Climate Change (IPCC): “Unequivocal” that climate is warming, “Very likely” that human activities are major driver.

The cause: mostly fossil fuels Carbon in atmosphere

IPCC Report: A conservative document Spons by U.N. & World Meteorological Org ~3000 scientists compile the 6-yr reports Based on tens of thousands of peer- reviewed scientific papers published in hundreds of scientific journals Results arrived at by consensus

The major U.S. carbon polluters: Electric Power 41% 3/4 from coal Transportation 33% 3/4 from cars and trucks

COAL 1 plant = 1 million cars SOLUTIONS: Energy efficiency & alternative energy sources Carbon capture & storage! (~50% price incr) Congress could mandate CCS

CARS 55 mpg by 2020 (hybrids today) Plug-in hybrids, attached to renewable electricity Gasoline tax of several $ per gallon “Externalities” of driving: $12 per gallon! 6 tons of CO2 / yr, 3 X car’s weight! SOLUTIONS:

The Solutions: Reduce CO2 emissions: Efficiency (use less) Renewables (solar, wind) Nuclear power Carbon capture and storage More broadly: Preserve, replant forests Limit population growth

The best choice: Energy efficiency!

Bicycling

Pedestrian zones, pedestrian streets

Light rail for NW Arkansas!

Renewables: Wind

Photovoltaics

Solar-thermal electricity

Active solar heating

Passive (or direct) solar

Geothermal energy For electricity: For heating & cooling:

Biofuels biofuels from grasses… … and agri waste From corn today: bad idea! With research:

Also: Nuclear power No greenhouse gases ! Serious drawbacks (proliferation etc.) MUCH safer than fossil fuels. China, India

20 leading climate scientists published a paper in Nature in Sep 2009: Our present 390 ppm atm CO2 concentration is already unsustainable and dangerous. We need to move it back to 350 ppm asap, in order to hold the temp increase to 2 o C. James Hansen, NASA’s cilmatologist Paul Crutzen Nobel Prize, Chem.

What’s needed: 60% global emissions reduction by Converge on 1.5 tons / person-yr India: emits 1 ton / person-yr today US: emits 20 tons / person-yr --must reduce by 90% Europe: reduce by 80%. But emissions are increasing, not decreasing!

THANK YOU! ART HOBSON Website: physics.uark.edu/hobson We’re all in this together! Thank you