Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land-use change, we found that corn-based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on U.S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products.

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Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change

Human activities are releasing tiny particles (aerosols) into the atmosphere. These human-made aerosols enhance scattering and absorption of solar radiation. They also produce brighter clouds that are less efficient at releasing precipitation. These in turn lead to large reductions in the amount of solar irradiance reaching Earth's surface, a corresponding increase in solar heating of the atmosphere, changes in the atmospheric temperature structure, suppression of rainfall, and less efficient removal of pollutants. These aerosol effects can lead to a weaker hydrological cycle, which connects directly to availability and quality of fresh water, a major environmental issue of the 21st century.

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Aerosols, climate, and the hydrological cycle

Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-analysis has so far examined the possible lack of evidence for changes or shifts at sites where no temperature change is observed. We used an enormous systematic phenological network data set of more than 125 000 observational series of 542 plant and 19 animal species in 21 European countries (1971–2000). Our results showed that 78% of all leafing, flowering and fruiting records advanced (30% significantly) and only 3% were significantly delayed, whereas the signal of leaf colouring/fall is ambiguous. We conclude that previously published results of phenological changes were not biased by reporting or publication predisposition: the average advance of spring/summer was 2.5 days decade � 1 in Europe. Our analysis of 254 mean national time series undoubtedly demonstrates that species’ phenology is responsive to temperature of the preceding

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European phenological response to climate change matches the warming pattern

Differential-Difference Equations. By Richard Bellman and Kenneth L. Cooke. Pp. xvi, 465. 1963. (Academic Press)

https://grassrootsinnovations.files.wordpress.com/2012/03/smith-et-al-2005-transtn-governance.pdf

The governance of sustainable socio-technical transitions

Climate change 2001, the scientific basis, chap. 8: model evaluation. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change IPCC

Contribution of Working Group 1 to the Third Assessment Report of the Intergovernmental Panel on Climate Change

Climate models—evaluation

Based on the material in the IPCC Second Assessment Report, this paper expands and clarifies the scientific and technical issues relevant to interpreting the objective of the UN Framework Convention on Climates Change as stated in Article 2, requiring stabilization of greenhouse gas concentrations. It first reviews the results of a range of standardized calculations used to analyse the relationships between emissions and concentrations for several levels of atmospheric CO{sub 2} stabilization, including two pathways to reach each level. It then considers the effect of other greenhouse gases and sulphate aerosol (from SO{sub 2} emissions) and estimates the temperature and sea level changes associated with the various stabilization levels studied. Finally, it reviews the potential positive and negative impacts associated with the projected temperature and sea level changes and discusses the mitigation costs associated with stabilizing greenhouse gases. 26 refs., 16 figs., 12 tabs.

Stabilisation of atmospheric greenhouse gases: Physical, biological, and socio-economic implications

The method presented makes use of a division of the region of integration into closed rectangular elements. The velocity is taken to be constant in each element. The integral equation is reduced to a matrix equation which can be solved by an appropriate iteration approach. The derivation and solution of the matrix equation are discussed and the matrix elements are considered. The described concepts were implemented for a nonlifting parabolic-arc airfoil.

W Ogana

Papers

Climate change 2001, the scientific basis, chap. 8: model evaluation. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change IPCC

Contribution of Working Group 1 to the Third Assessment Report of the Intergovernmental Panel on Climate Change

Climate models—evaluation

Stabilisation of atmospheric greenhouse gases: Physical, biological, and socio-economic implications

Numerical solution for subcritical flows by a transonic integral equation method