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Energy Efficiency and the Impact of Climate Change

This chapter explores the prospective climatic changes, impacts, and constraints related to energy efficiency and the demand for energy services. It discusses the greenhouse effect, human impacts on climate, and the key parameter of climate sensitivity. The chapter also examines the observed changes in global average surface temperature over time.

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Energy Efficiency and the Impact of Climate Change

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  1. Energy and the New Reality, Volume 1:Energy Efficiency and the Demand for Energy ServicesChapter 1: Prospective Climatic Change, Impacts and ConstraintsL. D. Danny Harveyharvey@geog.utoronto.ca This material is intended for use in lectures, presentations and as handouts to students, and is provided in Powerpoint format so as to allow customization for the individual needs of course instructors. Permission of the author and publisher is required for any other usage. Please see www.earthscan.co.uk for contact details. Publisher: Earthscan, UKHomepage: www.earthscan.co.uk/?tabid=101807

  2. Two strong reasons for becoming more efficient in the use of energy: • Global Warming (discussed this hour) • Peak oil (dealt with in transportation PS)

  3. Heating trapping (“forcing”) due to variations in greenhouse gas (GHG) concentrations over the past 45 million years (Ma), as inferred from various lines of geological evidence, compared with the range of GHG forcing projected by 2100 under business as usual scenarios. The last time the forcing or heat trapping was a high as is projected for 2100, there was no ice anywhere on this planet.

  4. Controls over the Earth’s Climate • The Earth’s climate is governed by the balance between absorption of solar radiation and emission of infrared radiation • Any imposed alteration in either term is called a radiative forcing • Following a radiative forcing, the temperatures of the Earth’s surface and atmosphere will naturally adjust to bring solar absorption and infrared emission back into balance

  5. The “greenhouse” effect • Refers to the partial absorption by certain gases in the atmosphere of infrared radiation emitted by the Earth’s surface • Because absorption of any radiation (whether solar or infrared) has a warming effect, this makes the climate warmer than it would be otherwise (by about 33ºC for the naturally-occurring greenhouse effect) • The key GHGs are: water vapour, CO2, ozone (O3), methane (CH4) and nitrous oxide (N2O)

  6. Human Impacts on Climate • Humans have directly emitted and increased the concentrations of CO2, CH4, N2O and various artificial GHGs (CFCs, HCFCs, HFCs, SF6), and pollutant emissions (NOx, CO and hydrocarbons) have lead to an increase in ground-level ozone • This in turn has caused a radiative forcing so far of about 2.5-3.5 W/m2 • If CO2 alone were to double, the radiative forcing would be about 3.75 W/m2 • Thus, the GHG increases so far are already equivalent to a 70-90% increase in CO2

  7. Figure 1.1 Variation in CO2 and CH4 Concentration

  8. The trapping of radiation initiates a series of feedbacks that ultimately determine how much warming we will eventually get. Some of the key feedbacks are: • Warming leading to more water vapour (which is a GHG) in the atmosphere, causing further warming • Warming lead to melting back of ice and snow (which otherwise reflect solar radiation), leading to more absorption of solar radiation at the surface and more warming

  9. The key parameter in the whole global warming issue is called the climate sensitivity.The is defined as the eventual (i.e., after the climate system has had enough time to adjust) global average warming for a fixed doubling of the atmospheric CO2 concentration

  10. Four independent lines of evidence are in broad agreement in indicating that the climate sensitivity is highly likely (say, 90% probability) to lie between 1.5ºC and 4.5ºC.That is, we expect each CO2 doubling (or its radiative equivalent) to eventually warm the climate by 1.5-4.5 C in the global mean.

  11. The four lines of evidence are: • Simulations of individual feedback processes with 3-D coupled atmosphere-ocean climate models • Comparison of observed global average warming over the past century (0.6-0.8ºC) and the gradual increase in estimated net radiative forcing (as GHGs have increased in concentration) over this time period

  12. Comparison of estimated global mean temperature changes and radiative forcings at various times during the geological past • Comparison of inferred and simulated natural variations in the atmospheric CO2 concentration during the last few 100 million years with different assumed values for the climate sensitivity (which plays a critical role in initiating processes that eventually limit the magnitude of slow, natural fluctuations in CO2 concentration)

  13. Thus, by the time we get the radiative equivalent of 4 x pre-industrial CO2 concentration (the end of this century under business-as-usual scenarios), we can expect an eventual global mean warming of 3.0-9.0ºC (2 doublings at 1.5-4.5ºC each, assuming a linear response)

  14. Figure 1.4 Global mean temperature change for business-as-usual and aggressive (near zero emissions before 2100) emission-reduction scenarios in which the CO2 concentration is stabilized at 450 ppmv

  15. Supplemental Discussion: What has been observed so far?

  16. Figure 1.2 Variation in global average surface temperature, 1856-2009

  17. 0.8 Esper 2002 Huang 2004 0.6 Rutherford 2005 Moberg 2005 C) 0.4 Mann et al 2008 o Instrumental 0.2 Temperature Change ( 0.0 -0.2 -0.4 -0.6 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 Year Figure 1.3 Reconstructed and directly observed (‘Instrumental’) variation in NH surface temperature

  18. Figure 1.5 Business as usual change in global mean temperature in the context of observed or inferred past variations

  19. Sea ice extent, Sept 2005 (white) and average extent during the 1980s (pink line) Source: National Snow and Ice Data Center (NSIDC), USA, http://nsidc.org/news

  20. Sea ice extent, Sept 2007 Source: NSIDC, http://nsidc.org/news

  21. Sea ice extent, Sept 2009 Source: NSIDC, http://nsidc.org/news

  22. September 2010

  23. September 2012

  24. Exhibit 1-40: Minimum annual extent of Arctic sea ice (occurring in Sept of each year) Source of data: National Snow and Ice Data Center, Boulder, Colorado

  25. Summer Melting of Greenland Ice Cap Source: Konrad Steffen (cires.colorado.edu/steffen/greenland/melt2005)

  26. Source: Fettweis et al (2007), Geophysical. Research Letters 34, L05502

  27. Sea level rise – 20 cm since 1880 Source: IPCC 2007, AR4, WG1

  28. Major Impacts of Concern • Sea level rise of 6-12 m over several centuries to a 1000 years or more • Increased occurrence of drought, with major (20-30% and more) reductions in food production in many regions • Increased water stress in vulnerable regions • Species extinction (1/3 to ½ this century) • Acidification of the oceans

  29. Source: Nature 447, 145-147 (2004)

  30. Source: Nature 439, 143-144 (2006)

  31. Source: Nature 442, 978-980 (2006)

  32. Dissolution effects on coccoliths Source: Ruttimann (Nature 442, 978-980, 2006)

  33. What are the solutions? • More efficient use of energy • Moderation in our material demands • Massive deployment of renewable energy

  34. United Nations Framework Convention on Climate Change (1992) • Ratified (and therefore accepted) by almost every country in the world • Declares as its goal the “stabilization of greenhouse gas concentrations in the atmosphere at a level that prevent dangerous anthropogenic interference in the climate system” • To be “safe” in choosing allowed concentrations, we have to assume that the climate sensitivity is near the high end of the uncertainty range (i.e., around 4.5ºC)

  35. UNFCC (continued) • Any given real CO2 concentration corresponds to a higher effective concentration when we add in the heating effect of other GHGs • Thus, 450 ppm CO2 corresponds to at least 560 ppmv (a doubling of the pre-industrial concentration of 280 ppmv) • As a doubling could warm the climate by 4.5ºC, and if this is unacceptable, then we need to keep the real CO2 concentration to below 450 ppmv if we are to play it safe (as required by the UNFCCC). • We are currently (2012) at about 390 ppmv.

  36. Cancun Accord, Article 4 “The Conference of Parties … recognizes that deep cuts in global greenhouse gas emissions are required according to science … with a view to [holding] the increase in global average temperature below 2oC above preindustrial levels, and that the Parties should take urgent action to meet this goal … also recognizes the need to consider … strengthening the long-term goal to a global temperature rise of 1.5oC.” Source: United Nations, Framework Convention on Climate Change, The Cancun Agreements: Outcome of the work of the Ad Hoc Working Group on Long-term Cooperative Action under the Convention, FCCC/CP/2010/7/Add.1 (15 March 2011), online: <http://unfccc.int/resource/docs/2010/cop16/eng/07a01.pdf>

  37. Business-as-usual scenario: 3-6oC global mean warming by 2100 Source: IPCC AR5, WG1, SPM Fig. 7a

  38. Table 1 of WG2 SPM summarizes the risks of 2oC and 4oC global mean warming in such areas as: • Wildfires • Drought • Food production • Forest health • Human health are mortality • Sea level rise • Ocean acidification (caused by the CO2 increase associated with various amounts of warming)

  39. AR5 WG2 finds that • “Very High” risks are expected in almost all impact areas with 4ºC warming and current levels of adaptation. These risks can be reduced to “medium” in some sectors with high levels of adaptation • “Medium” to “Very High” risks are expected even for a 2ºC warming with current levels of adaptation. These risks can be reduced to “Medium” for all sectors with strong adaptation.

  40. Total allowed cumulative emissions vs allowed global mean warming Source: IPCC AR5, WG1, SPM Fig 10

  41. Where is Canada heading?

  42. Canadian conventional and tar sands oil production, historical and industry hoped-for • 7.0 • Source: CAPP (2013)

  43. Source: CAPP (2013)

  44. All proposed pipelines and more are needed to meet tar sands expansion plans • Source: • CAPP (2013)

  45. Decomposition of past and future fossil fuel CO2 emissions according to the Kaya identity • Emission = Population x GDP/P x Energy Intensity x C Intensity, or • E = P x ($/P) x (MJ/$) x (kgC/MJ)

  46. Figure 1.6b Global population and global mean GDP/P and energy and carbon intensities

  47. Figure 1.6a Global population, GDP, primary energy demand and CO2 emission

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