Jan 2013 The assessment by the imagesThe images have been taken and arranged from the various chapters as an education resourceText in blue is Climate Emergency Institute
Between January 14th and April 12th : Please go to Review and Comment to providecomments on the draft. http://ncadac.globalchange.gov/
For the US assessment images skip to slide 30 4-5 Response in brief 6-7 Risk and decision making slides 8-29 Science slides30- 86 US assessment slides
Response in briefThe US draft climate change assessment report (which includes global content) is a most important document toread and to provide input on.The US Global Change department has produced an assessment that is very well presented for public informationand in general covers the issues very well.There is much to be learned from this assessment.It provides information by which the public could assess many of the risks but it is not an actual risk assessment.Even so the assessment makes it clear America and the world are today in a state of global climateemergency.The greatest risks to all humanity and our planet which result from the rapid loss of Arctic albedo cooling are notincluded. This is a grave omission.The multiple combined adverse impacts to crops that are recorded are not reflected in the predictions of foodsecurity, and so the risk to food security is greatly understated. This is most dangerously misleading to Americans.The assessment fails to say that only DECARBONIZATION of the world economy, or stopping all industrial agecarbon emissions, can stop the global temperature and ocean acidification continuing to increase
Greatest fundamental fatal error. The assessment fails to say that only stopping carbonemissions can lower the atmospheric CO2 level or stabilize it in the long term- zero carbonemissions. Reducing emissions will not prevent eventual global climate catastrophe from theaccumulation of CO2 in the atmosphere. The assessment does not say we have to totallyconvert off fossil fuels onto clean zero carbon and everlasting energy (which is abundant) toprevent eventual planetary catastrophe.Key Message 5. Science Past emissions of heat-trapping gases have already committed the world to a certain amount of futureclimate change. How much more the climate will change depends on future emissions and the sensitivityof the climate system to those emissions. A certain amount of climate change is already inevitable due tothe build-up of CO2 in the atmosphere from human activities over the past few centuries. Even if the netCO2 emissions could be reduced to zero today, the human-induced perturbation to the global carboncycle would persist for thousands of years (NRC 2011).Key Messages Mitigation 1. There are long time lags between actions taken to reduce carbon dioxide emissions and their effectson its atmospheric concentration. Mitigation efforts that only stabilize global emissions will therefore notreduce atmospheric concentrations of carbon dioxide, but will only limit their rate of increase. ….… Mitigation refers to actions that reduce the human contribution to the planetary greenhouse effect.Mitigation actions include lowering emissions of greenhouse gases like carbon dioxide and methane, andparticles that have a warming effect.
Decision making.A comprehensive integrated risk assessment of climate change impacts has not beenpublished.
Note: increasing uncertainty (from model results) over time.There is also multiplication cascade of uncertainties from model results at many stages of assessment ending atpopulation health impacts. These increase risks of delaying action.
Figure 16: Only Human Influence CanExplain Recent Warming Caption: Changes in surface airtemperature at the continental and globalscales can only be explained by the influence of humanactivities on climate. The black linedepicts the observed changes in ten-year averages.The blue shading represents estimatesfrom a broad range of climate simulationsincluding solely natural (solar andvolcanic) changes. The pink shading shows simulationsincluding both the natural and humancontributions. (Figure source: Jones et al. submitted)
Carbon dioxide levels in the atmosphere are currently increasing at a rate of 0.5% per year.Atmospheric levels reached 392 parts per million in 2012, higher than anything the Earth has 1experienced in over a million years (the figure shows the ice core record for CO2 levels over thelast 800,000 years).Globally, over the past several decades, about 80% of carbon dioxide emissions from humanactivities came from burning fossil fuels, while about 20% came from deforestation and otheragricultural practices.Some of the carbon dioxide emitted to the atmosphere is absorbed by the oceans, and some isabsorbed by vegetation. About 45% of the carbon dioxide emitted by human activities in thelast 50 years is now stored in the oceans and vegetation. The remainder has stayed in theatmosphere, where carbon dioxide levels have increased by 40% relative topre-industrial levels.
Methane levels in the atmosphere have increased mainly as a result of agriculture including raising livestock (which produce methane in their digestive tracts); mining coal, extraction andtransport of natural gas, and other fossil fuel-related activities; and waste disposal including sewage and decomposing garbage in landfills. About 70% of the emissions of atmosphericmethane now come from human activities. Atmospheric amounts of methane leveled off from1999-2006 due to temporary decreases in both human and natural sources, but have been increasing again since then.Since preindustrial times, methane levels have increased by 250% to their currentlevels of 1.85 ppm.Methane has direct radiative effects on climate because it traps heat, and indirect effects onclimate because of its influences on atmospheric chemistry. An increase in methaneconcentration in the industrial era has contributed to warming in many ways (Forster et al.2007). Increases in atmospheric methane, VOCs, and nitrogen oxides (NOx) are expected todeplete concentrations of hydroxyl radicals, causing methane to persist in the atmosphere andexert its warming effect for longer periods (Montzka et al. 2011; Prinn et al. 2005). The hydroxylradical is the most important “cleaning agent” of the troposphere, where it is formed by acomplex series of reactions involving ozone and ultraviolet light (Schlesinger and Bernhardt2013).
Other greenhouse gases produced by human activities includenitrous oxide, halocarbons, and (ground level) ozone.Nitrous oxide levels are increasing primarily as a result of fertilizer use and fossil fuelburning.They have increased by about 20% relative to pre-industrial times.The strongest direct effect of an altered nitrogen cycle is through emissions of nitrous oxide(N2O), a long-lived and potent greenhouse gas that is increasing steadily in the atmosphere (Forster et al. 2007; Montzka et al. 2011).Globally, agriculture has accounted for most of the atmospheric rise in N2O (Matson et al. 1998;Robertson et al. 2000). Roughly 60% of agricultural N2O derives from high soil emissions thatare caused by nitrogen fertilizer use.Animal waste treatment and crop-residue burning account for about 30% and about 10%,respectively (Robertson 2004).The U.S. reflects this global trend: around 75% to 80% of U.S.human-caused N2O emissions are due to agricultural activities, with the majority beingemissions
The nitrogen cycle affects atmospheric concentrations of the three most important human-caused greenhouse gases: carbon dioxide, methane, and nitrous oxide.Once created, a molecule of reactive nitrogen has a cascading impact on people and ecosystems as itcontributes to a number of environmental issues. (Figure adapted from EPA 2011a; Galloway et al. 2003,with input from USDA). (USDA contributors were Adam Chambers and Margaret Walsh.) These problems persist until the reactive nitrogen is either captured and stored in a long-term pool, like themineral layers of soil or deep ocean sediments, or converted back to nitrogen gas (N2) (Baron et al. 2012;Galloway et al. 2003).
-- lower- atmosphere ozone levels have increased because of human activities,including transportation and manufacturing. These produce what are known as ozoneprecursors: air pollutants that react with sunlight and other chemicals to produce ozone.Since the late 1800s, average levels of ozone in the lower atmospherehave increased by more than 30% (Lamarque et al. 2005).Much higher increases have been observed in areas with high levels of air pollution, and lesserincreases in remote locations where the air has remained relatively clean
Jan 2013 The assessment in the imagesThe images have been taken and arranged from the various chapters as an education resourceText in blue is Climate Emergency Institute
IPCC 2007 IPCC 2014 4th assessment 5th assessmentsocio-economic socio-economicscenarios scenarios Carbon Emissions Atmospheric CO2 concentration Global average Temperature change
Caption: Projected change (°F) in annual average temperature over the period 2071-2099(compared to the period 1971-2000) under a low emissions pathway (RCP 2.6, left graph) thatassumes rapid reductions in emissions and a high pathway (RCP 8.5, right graph) that assumescontinued increases in emissions. (Figure source: NOAA NCDC / CICS-NC. Data from CMIP5.)
°C IPCC 2007 assessment scenarios IPCC 2014 assessment scenarios US Global Change Climate Assessment Draft Jan 2013
Maps show projected change in average surface air temperature in the later part of this century (2070-2099) relative tothe later part of the last century 6 (1971-1999) under a scenario that assumes substantial reductions in heat trappinggases (B1, left) and a higher emissions scenario that assumes continued increases in global emissions (A2, right). Thesescenarios are used throughout this report 9 for assessing impacts under lower and higher emissions. Projected changesare 10 averages from 15 CMIP3 models for the A2 scenario and 14 models for the B1 scenario. (Figure source: adaptedfrom (Kunkel et al. 2012).)
Temperature change projections new IPCC scenariosMaps show projected change in average surface air temperature in the later part of this century(2070-2099) relative to the later part of the last century 6 (1971-1999)
Caption: Projected percent change in annual average precipitation over the period 2071-2099(compared to the period 1901-1960) under a low emissions pathway (RCP 2.6) that assumesrapid reductions in emissions and a high pathway (RCP 8.5) that assumes continued increases inemissions. Teal indicates precipitation increases, and brown, decreases. Hatched areas indicateconfidence that the projected changes are large and are consistently wetter or drier.
Projected percent change in seasonalprecipitation for 2070-2099(compared to the period 1901-1960)under an emissions scenario thatassumes continued increases inemissions (A2). Teal indicatesprecipitation increases, and brown,decreases. Hatched areas indicateconfidence that the projected changesare large and are consistently wetter ordrier. White areas indicate confidencethat the changes are small. Wetregions tend to become wetter whiledry regions become drier. In general,the northern part of the U.S. isprojected to see more winter andspring precipitation, while theSouthwest is projected to experienceless precipitation in the spring. (Figuresource: NOAA NCDC / CICS-NC. Data 11from CMIP3; analyzed by MichaelWehner, LBNL.)
Polar regionsKey Message 11. Summer Arctic sea ice extent, volume, and thickness have declined rapidly, especially north of Alaska. Permafrost temperatures are rising and the overall amount of permafrost isshrinking. Melting of land and sea-based ice is expected to continue with further warming.
Reductions in sea ice increase the amount of the sun’s energy that is absorbed by the ocean. This leads to a self-reinforcing climate cycle, because the warmer ocean melts more ice, leaving moredark open water that gains even more heat. In autumn and winter, there is a strong release of this extra ocean heat back to the atmosphere. This is a key driver of the observed increases in air temperature in the Arctic (Screen and Simmonds 2010; Serreze et al. 2008). This strong warminglinked to ice loss can influence atmospheric circulation and patterns of precipitation, both within and beyond the Arctic (for example, Porter et al. 2012). There is growing evidence that this hasalready occurred (Francis and Vavrus 2012) through more evaporation from the ocean, whichincreases water vapor in the lower atmosphere.
On land, changes in permafrost providecompelling indicators of climate change as theytend to reflect long-term average changes in climate.Borehole measurements are particularly usefulasthey provide information from levels belowabout 10-meter depth where the seasonal cyclebecomes negligible. Increases in boreholetemperatures over the past several decades are apparent at various locations, including Alaska,northern Canada, Greenland, and northern Russia. The increases are about 3.6°F at the twostations in northern Alaska (Deadhorse and13 West Dock). In northern Alaska and northernSiberia where permafrost is cold and deep, thawof the entire permafrost layer is not imminent.However, in the large areas of discontinuous permafrost of Russia, Alaska, and Canada,average annual temperatures are sufficientlyclose to freezing that permafrost thaw is a riskwithin this century. Thawing of permafrost canrelease methane into the atmosphere,amplifying warming, US Gl Change Jan 2013
Changes in terrestrial ecosystems in Alaska and the Arctic may be influencing the global climatesystem.Permafrost soils throughout the entire Arctic contain almost twice as much carbon as theatmosphere (Schuur and Abbott 2011). Warming and thawing of these soils increases therelease of carbon dioxide and methane through increased decomposition and methaneproduction.Thawing permafrost also delivers organic-rich soils to lake bottoms, where decomposition inthe absence of oxygen releases additional methane (Walter et al. 2006).Extensive wildfiresalsorelease carbon that contributes to climate warming (Balshi et al. 2008; French et al. 2004;Zhuang et al. 2007). T
Climate change effects on agriculture will have consequences for food security bothin the U.S. and globally, not only through changes in crop yields, but also changes inthe ways climate affects food processing, storage, transportation, and retailing.
Figure 6.4: Crop Yield Response toWarming in California’s Central ValleyCaption: Changes in climate through thiscentury will affect crops differently becauseindividual species respond differently towarming. Crop yield responses for eightcrops in the central valley of California areprojected under two emissions scenarios,one in which heat-trapping gas emissionsare substantially reduced (B1, in gold) andanother in which these emissions continueto grow (A2, in red). The crop model used inthis analysis (DAYCENT) assumes that watersupplies and nutrients are maintained atadequate levels.The lines show five-year moving averages forthe period from 2000 to 2097 with the yieldchanges shown as differences from the 2000baseline. Yield response varies among cropswith alfalfa showing only year-to-yearvariation across the whole period, whilecotton, maize, wheat, and sunflower beginto show yield declines early in the period.Rice and tomato do not show a yieldresponse until the latter half of the periodwith the higher emissions scenario resultingin a larger yield response (Lee et al. 2011).