Global WarmingPrediction L. David Roper Professor Emeritus of Physics Virginia Polytechnic Inst. & St. Univ. email@example.com http://arts.bev.net/RoperLDavid http://www.roperld.com/science/GlobalWarmingPrediction.htm Global Warming and Peak Oil may be the greatest challenges that humans have encountered in the last 10,000 years.
Global Warming Prediction • It is very important to account for fossil-fuels depletion when calculating Global Warming predictions. • Otherwise, it might be assumed that more carbon can be put into the atmosphere from burning fossil fuels than physically possible. • Calculating fossil-fuels depletion is not exact, but can be estimated reasonably well.
Fossil Fuels Global Warming • Fit depletion curves to extraction data for coal, crude oil and natural gas using discoveries data and reserves estimates. • Calculate the carbon emitted due to burning fossil fuels and the CO2 concentration in the atmosphere, accounting for residence time. • Calculate the Earth temperature due to the CO2 in the atmosphere, including time lag. • Consider triggering of other effects that raise temperature, including temperature feedbacks that increase CO2 concentration.
Verhulst Function for resources depletion. Q = amount already extracted + amount left to be extracted = total amount to be extracted n ≠ 1 allows asymmetry. Verhulst Function: An asymmetric peaked curve.
Oil discoveries will not allow higher average extraction. Peak Oil Skewed toward later times.
You can’t extract it if you have not discovered it! Areas under both curves are the same. That is, the amount discovered equals the amount extracted. discoveries extraction The areas under the two curves are the same: ~2x1012 barrels.
Gas discoveries will not allow higher average extraction. Peak Gas Skewed toward later times.
You can’t extract it if you have not discovered it! Areas under both curves are the same. That is, the amount discovered equals the amount extracted. discoveries The areas under the two curves are the same: ~8x1015 cu. ft.
Peaks between 2060 & 2100 Double known coal. Unlikely! Known existent coal (EIA)
Factors and Assumptions • Coal = 50% carbon, short ton = 0.907 tonnes • Crude oil = 84% carbon, bbl = 0.136 tonnes • Natural gas = 76% carbon, tcf = 0.0189 tonnes • CO2 concentration in ppmv = 0.47 x gigatonnes carbon emitted (may increase with high concentration; i.e., may be nonlinear; see later) • Climate sensitivity = 3°C for doubling CO2 • 25% of fossil fuels are used to make useful materials or are lost instead of being burned. • Background year 1700 CO2 concentration = 280 ppmv
20% left after 250 years 10% left after 2000 years 6% left after 10,000 years
Equation for CO2 left in nth year for emissions in all previous years.
Coal CO2 emissions and CO2 concentration contribution. Shift in ppmv is due to CO2 residence time.
Crude-oil CO2 emissions and CO2 concentration contribution. Shift in ppmv is due to CO2 residence time.
Natural-Gas CO2 emissions and CO2 concentration contribution. Shift in ppmv is due to CO2 residence time.
Fossil-Fuels CO2 emissions and CO2 concentration contribution.
CO2 concentration due to Fossil-Fuels burning Peaks at about 2110.
CO2 concentration due to Fossil-Fuels burning + background Below measured data, as it should be.
Non-Fossil-Fuels CO2 Emissions • Deforestation • Soil depletion • Cement production • Domestic animals Assume that non-fossil-fuels CO2 concentration is proportional to concentration due to burning fossil fuels.
Fit of CO2 Concentration Data to Fossil-Fuels Emissions NFF=14% of FF Pre-fossil-fuels industrialization
CO2 concentration due to Fossil-Fuels burning + Non-fossil-fuels sources;latter assumed proportional to fossil-fuels concentration.
CO2 concentration due to Fossil-Fuels burning + Non-fossil-fuels + background 465 ppmv It peaks at about 2100 instead of rising into the next century as many assume. Carbon-dioxide concentration due to burning fossil fuels with non-fossil fuels emissions, assuming that no Earth states are triggered.
Climate Sensitivity (s) Earth average atmospheric temperature rise due to doubling the carbon-dioxide concentration in the atmosphere. Accounts for fast feedbacks, such as ice melting. The average is about 3 degrees Celsius. It must be applied each year using the carbon-dioxide concentration for that year. C0=concentration for reference year (1700).
Climate-Response Function There is a time lag for the atmospheric temperature after carbon emissions. Due to energy absorbed and released later in mostly the oceans, but also in ice. Fit of two hyperbolic tangents to the data. Data errors are large.
Climate-Response Function The climate-sensitivity function is multiplied by a series of two hyperbolic tangents: Temperature lag is due to energy absorbed and released later in mostly the oceans, but also in ice.
1.3 degrees C Although the temperature is not extremely high, it hangs around for a long time. Close to the current measured value. Does not account for fluctuations due to global dimming.
Why such a high projection?! Disaster region! Peak in this calculation. Ice age to current interglacial is about 8 degrees C in Antarctica and about half that in the temperate regions. 8°C Temperature & CO2 are mutually reinforcing (positive feedback).
Assume carbon sequestration or a coal-burning moratorium. Probably optimistic!
CO2 is somewhat reduced by carbon sequestration or a coal-burning moratorium. 430 ppmv; reduced from 465
Temperature is somewhat reduced by carbon sequestration or a coal-burning moratorium. 1.1 degrees C; reduced from 1.3 Will we have waited too late?!
Temperature is increased due to doubled coal extraction. 1.65 degrees C Instead of 1.3
Temperatures for some of the cases considered DoubleCoal Coal Moratorium or Carbon Sequestration Assumes that there is no triggering of Earth states.
!Some Nightmares! • Suppose concentration/emissions factor changes with increasing concentration from 0.47 to 0.94 (land and ocean become saturated with CO2). • Suppose permafrosted tundra release of carbon during the next century (example of temperature feedback). • Suppose climate sensitivity changes from 3 to 4 over the next two centuries. (It is known that it changes to 6 over millennia because of slow feedbacks.)
Suppose concentration/emissions factor changes with concentration from 0.47 to 0.94 (doubled). 820 ppmv Assumes hyperbolic-tangent change with 450 ppmv break point and 50 ppmv width. Disaster Region! Due to land and oceans being saturated with carbon dioxide.
Suppose emissions/concentration Factor changes with concentration from 0.47 to 0.94 (doubled). 2.7 degrees C Dangerously high temperatures
Assume permafrosted tundra release of carbon. Total 400 gigatonnes Example of temperature feedback; there are other temperature feedbacks.
Total CO2 concentration including permafrosted tundra release of carbon 555 ppmv Disaster Region!
Temperature including permafrosted tundra release of carbon. 1.8 degrees C Disaster Region!
Worst case CO2 concentration 1110 ppmv !Calamitous! Most likely fossil-fuels depletion, CO2 feedback & carbon release in Arctic
Worst case temperature Will cause terrible catastrophes for human life. (See Six Degrees: Our Future on a Hotter Planet by Mark Lynas.) 4.5 degrees C for climate sensitivity change to 4 3.5 degrees C for climate sensitivity = 3 Approximately the same temperature change between the last glacial maximum and now!
Temperatures for some of the cases considered DoubleCoal Coal Moratorium or Carbon Sequestration !Could a coal moratorium keep those disastrous Earth states from triggering?!
Fossil Fuels Burning Reduction Reduces temperature below now, which might keep from triggering carbon releases and other temperature-raising feedbacks.
Conclusions • Peaking fossil fuels keeps CO2 concentration from going extremely high, unless it triggers other effects. • Since temperature rise of about 0.8°C from 18th century is already causing disastrous events, the continuing increase of another 1°C or more will cause even more disasters and may other Earth changes that will cause a higher temperature. • The peaking of fossil fuels may be as large immediate disaster as is global warming.
World Population Projections Population with renewable energy Fit of population to available fossil-fuels energy 1950-2006. Population without renewable energy
Next Major Ice Age with Global Warming Effect Accounting for claim that Earth average temperature changes are about half Antarctica average temperature changes.
This lecture is on the Internet, along with other related lectures: • http://www.roperld.com/science/GlobalWarmingPrediction.ppt • http://www.roperld.com/science/energy.ppt (Future Energy) • http://www.roperld.com/science/energyGWNMIA.ppt (Energy, Global Warming and the Next Major Ice Age)