GEOG 401 Climate Change. After Taking Stock, Where Do We Go From Here?

Transcription

1 GEOG 401 Climate Change After Taking Stock, Where Do We Go From Here?

2 What We Know (1) The planetary system will seek radiative equilibrium by changing surface temperature whenever the equilibrium is disturbed Radiatively active gases (greenhouse gases) absorb outgoing longwave radiation The impacts of human activities on the earth s natural systems (including climate) have undergone spectacular acceleration in the past years.

3 Steffen et al. (2015, The Anthropocene Review 2: 81-98)

4 Steffen et al. (2015, The Anthropocene Review 2: 81-98)

5 What We Know (2) Ongoing changes in atmospheric chemistry are occurring at a rate never previously seen

6 What We Know (3) Temperature is rising rapidly, as expected, because of the unprecedented human-caused changes to the planet

7 What We Know (4) Temperature change is setting off a series of responses within the coupled climate system Increases in global evaporation and precipitation Increasing global ET Joshua Fisher, JPL

8 What We Know (5) Temperature change is setting off a series of responses within the coupled climate system Changes in global cloud amount and distribution Norris et al. (2016, Nature)

9 What We Know (6) Temperature change is setting off a series of responses within the coupled climate system Changes in heavy rainfall events Trends in Magnitude Trends in Frequency Fig. 1. Maps showing the results for statistically significant trends (5 % level) in the magnitude (a) and frequency (b) of heavy precipitation. Analyses are performed at the annual scale. Blue (red) pixels show grid cells with an increasing (decreasing) trend. The thicker black lines refer to the seven regions considered in this study Mallakpour and Villarini (2016, Theoretical and Applied Climatology 130: )

10 What We Know (7) Temperature change is setting off a series of responses within the coupled climate system Changes in drought occurrence Cook et al. (2015, Science Advances 1, doi: /sciadv )

11 What We Know (8) Temperature change is setting off a series of responses within the coupled climate system Glaciers are retreating worldwide Roe et al. (2017, Nature Geoscience)

12 What We Know (9) Temperature change is setting off a series of responses within the coupled climate system Greenland ice sheet is losing mass Talpe et al. (2017, Journal of Geodesy 91: ) van den Broeke et al. (2017, Current Climate Change Reports)

13 What We Know (10) Temperature change is setting off a series of responses within the coupled climate system Antarctic ice sheet is losing mass NASA (2017) Talpe et al. (2017, Journal of Geodesy 91: )

14 What We Know (11) Temperature change is setting off a series of responses within the coupled climate system Changes in sea level Nerem et al. (2018, PNAS, doi: /pnas )

15 What We Know (12) Temperature change is setting off a series of responses within the coupled climate system Ocean acidification Seattle Aquarium

16 What We Know (13) Temperature change is setting off a series of responses within the coupled climate system Coral Bleaching

17 What We Know (15) Positive feedbacks in the system will amplify the effects of human-caused increases in greenhouse gases, for example: Ice-albedo feedback Water vapor feedback CO2 feedback Methane feedback

18 What We Know (16) If humanity stays on its present course, catastrophic changes will follow, making the planet much less livable within this century: Heat waves Coastal and island inundation More extreme weather: more intense hurricanes, more floods, more droughts Agriculture will become less productive in many areas Water supplies will be reduced in some areas Natural ecosystems will shift, adapt, or go extinct; along with other stressors, climate change is pushing us into the Earth s Sixth Mass Extinction Event

19 Now that we know, what do we do? Kyoto Copenhagen Paris - Trump Now what? Individual action Educate others climate/how-americans-think-about-climate-change-insix-maps.html State and local action Vote for environment Shame politicians who take money from polluting industries

20 What do we need to do to protect the future? INTERNATIONAL-NATIONAL-LOCAL: Replace fossil fuels with renewable energy sources as soon as possible (by when?) Wind, solar, hydro, geothermal, OTEC, tides, waves Biofuels Cooperate internationally to promote clean energy solutions COMMUNITY-FAMILY-INDIVIDUAL: Eat less meat Have smaller families Fly less Vote

21 How can we quicken the pace of transition to a green economy? Cap and trade? Carbon tax? Other?