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PPD132 /ESS182 Sustainable Development 2 Spring 2010. Lecture 6: Climate Change Professor Richard Matthew. Overview. Lecture on Climate Change Break Landscape: Easter island Group Projects. Lecture on Climate Change. Climate Change. Three issues: Physical science
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PPD132 /ESS182Sustainable Development 2Spring 2010 Lecture 6: Climate Change Professor Richard Matthew
Overview • Lecture on Climate Change • Break • Landscape: Easter island • Group Projects
Climate Change • Three issues: • Physical science • Impacts and vulnerabilities • Mitigation, adaptation and geoengineering
The Last 20,000 Years seems to have been Ideal for the Development of Human Societies. Is this a Historic “Sweet Spot” that Enabled Humans to Flourish? 4.5 oC Is this an Anthropomorphic “Sweet Spot”? Agriculture emerges 1.5 oC IPCC Summary for Policymakers (2 Feb. 2007) Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level.
Increases Decreases Land precipitation is changing significantly over broad areas Smoothed annual anomalies for precipitation (%) over land from 1900 to 2005; other regions are dominated by variability.
A Paleoclimatic Perspective Paleoclimate information supports the interpretation that the warmth of the last half century is unusual in at least the previous 1300 years. The last time the polar regions were significantly warmer than present for an extended period (about 125,000 years ago), reductions in polar ice volume led to 4 to 6 metres of sea level rise.
CO2 CH4 The atmospheric concentration of CO2 and CH4 in 2005 exceeds by far the natural range of the last 650,000 years
Climate Change • Climate change is already having significant adverse human impacts: • Contributing to violent conflict • Amplifying health problems • Deepening migration pressures • Weakening governance capacity • Introducing obstacles to poverty alleviation and development • Analysts predict that as global warming continues, these trends will worsen considerably
There is a fundamental asymmetry between the time scales that the climate system reacts to increases in greenhouse gases and the time scales to recover from such increases. There is a fundamental asymmetry between the time scales that the climate system reacts to increases in greenhouse gases and the time scales to recover from such increases. Sea Level Rise will Stabilizes in over 1000 years Reduction CO2 missions sooner, moves these delayed consequences downward and reduces the time required to stabilize the responses. Temperatures Stabilizes in about 500 Hundred years Carbon Dioxide Stabilizes in several Hundred years 100 Years Today 1000 Years
Climate Change: Mitigation, Adaptation and Geoengineering • Mitigation • The most obvious solution to the problems described above is to reduce greenhouse gas emissions. This could be done in four general ways: • (1) by improving the efficiency of energy use in transportation, buildings and other areas where there is considerable waste; • (2) by moving towards alternative sources of energy that do not emit greenhouse gases such as nuclear power and renewable forms such as wind and geothermal; • (3) by protecting natural carbon storage systems such as forest cover, and developing new ways of capturing and storing carbon; and • (4) by reducing consumption by changing behavior and reducing or reversing population growth.
Climate Change • In his 2006 report, Stern recommended that the world invest one percent of GDP into mitigation activities; following the evidence provided by the 2007 IPCC reports, he revised this upwards to 2% (Stern 2006; Burtraw and Sterner 2009). • The 2009 UN report Promoting Development, Saving the Planet, “recognizes a maximum temperature increase of 2˚C above pre-industrial levels as the target for stabilizing carbon concentrations at a level that prevents dangerous anthropogenic interference in the climate system. • This corresponds to a target greenhouse gas concentration (in terms of carbon dioxide equivalents (CO2e)) of between 350 and 450 parts per million (ppm) and to global emission reductions of the order of 50-80 per cent over 1990 levels, by 2050. In terms of actual emissions, this would be equivalent to a reduction from roughly 40 gigatons of carbon dioxide (GtCO2) at present to between 8 and 20 GtCO2 by 2050” (p. vi).
Climate Change • Adaptation through Innovation and Cooperation • A supplement/alternative to mitigation that does have widespread support is adaptation. • Adaptation is a socio-ecological process of change or adjustment to new or modified circumstances. Within the context of climate change, it is understood as actions that people take in response to, or in anticipation of changing climate conditions to reduce adverse impacts or take advantage of any opportunities that may arise.The need for, type and scale of adaptation depends on the kind of change taking place, as well as the vulnerability of people and natural systems to this change.
Climate Change • Geoengineering • If mitigation is not successful in stabilizing the global climate system, some scientists suggest that governments may need to explore geoengineering on a planetary scale. Proposals include taking steps to alter the reflectivity—or albedo—of the earth’s surface such as scattering dust particles in the atmosphere; developing artificial carbon storage systems; and introducing iron into the oceans to absorb atmospheric carbon dioxide by encouraging phytoplankton blooms.
Landscape: Easter Island • First colonial contact on Easter Sunday 1722 • Special territory of Chile since 1888 • Very isolated island • 63 square miles (15.3 x 7.6 miles) • 4800 inhabitants • Subtropical maritime climate (ranges from 64-82 degrees F) • Formed by three coalesced volcanoes • Dramatic and much studied history
Landscape: Easter Island • Thought to have been first settled around 300 CE; possibly much later 700-1100 CE • Famous for construction of Moai, statues in honor of dead ancestors—a symbiotic relationship between people and these statues • Statues required enormous labor and led to deforestation and warfare as the resource base collapsed • Slave raiders furtehr reduced the population • By 1877 only 111 people remained—population had fallen by 97% from 1722
