1 / 23

Impacts of CC

Impacts of CC. Section 2 – reading is at the bookstore. But first. Climate Change conference began yesterday Check it out. Your paper. And second. Field work on cc and gender … interested?. And Third. Consequences of climate change.

rosine
Télécharger la présentation

Impacts of CC

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Impacts of CC Section 2 – reading is at the bookstore

  2. But first Climate Change conference began yesterday Check it out

  3. Your paper And second

  4. Field work on cc and gender … interested? And Third

  5. Consequences of climate change “In nature, there are neither rewards nor punishments – there are consequences.” – Robert Ingersoll, 1833-1899

  6. Geological consequences Is it possible to unravel the climatic factors from other causes of geological change? Climatic events – waxing and waning of ice sheets, desiccation of continental interiors, drying up of oceans – had major impacts on the geology of the large parts of the Earth Question: were they ‘cause’ or ‘effect’? If ‘effect’ of plate tectonics and volcanism…

  7. 2 issues • Do shifts in the climate exert a significant feedback on tectonic activity (eg volcanism) by – say – changing the load on the Earth’s crust due to the build-up and collapse of polar ice sheets or changing sea levels? • If the climate can exert influence on tectonic activity, is it affected by extraterresrial effects (such as?)? • No agreement currently on whether climate change exerts a significant effect on tectonic activity • But – significant evidence to suggest there are various ways in which climate might create/help relieve stresses in the Earth’s crust

  8. Stresses in the Earth’s crust… Example: during the last ice age, the eruption of volcanoes in the Med occurred more often at times of rapid sea-level change Proposition: changes in the loading of the Earth’s crust by the build-up and collapse of ice sheets over northern Europe did influence the level of volcanic activity in the region Unclear: how this feeds back into climate change

  9. Variations in the day More subtle global effect: variations in the length of the day If atmosphere circulates more rapidly, principle of the conservation of angular momentum requires that the Earth should slow down – an ever so tiny amount – to compensate for this atmospheric acceleration due to a major ENSO warming event – equatorial winds speed up and Earth slows down During sudden changes of the climate  Earth could speed up or slow down by significant amounts  could set up stresses and strains in the crust  lead to increased volcanic activity  more climate changes

  10. Climate change -> volcanoes? • Was a big question during the Iceland volcano – April 2010 • “Iceland's Eyjafjallajokull has everyone discussing what causes volcanic eruptions. One controversial hypothesis suggests climate change may play a role”http://theweek.com/article/index/202085/does-global-warming-cause-volcanoes-to-erupt) • Melting ice could provoke large eruptions…If Iceland's ice caps thaw, their weight diminishes, "freeing magma from deep below ground." Heavily ice-capped volcanoes like those in the Aleutian islands of Alaska or Patagonia in South America could be most at risk. • But Volcanic activity is caused by "magma rising to the surface, not glaciers melting”

  11. Extreme weather events • “One swallow a spring does not make, and so a single extreme weather event does not necessarily signify climate change. But how many swallows do?” • Recent years: increasing frequency of strong hurricanes; total # same • Recent years: record-breaking warmth • Recent years: local and regional unusual intense rainfall and drought

  12. A warmer world  more thermal energy within the atmosphere and ocean-circulation system  some of that energy  greater evaporation (more rainfall) and wind speeds and storm size Therefore: as the world warms, so the frequency of extreme weather events is likely to increase What of the intensity and frequency of heat waves? (strong psychological factor) Also likely to increase. Heat waves over parts of US and Europe coincided with a specific atmospheric circulation pattern that is intensified by ongoing increases in greenhouse gases

  13. Hotter? Expect more extreme weather events But not all extreme weather events are attributable to CC Need to know: what is expected with natural variability assuming no carbon dioxide forcing and with climate forcing from additional anthropogenic greenhouse gases UK HadCM3 model: an exceptionally warm summer up to 2020 will become a normal summer by the 2040s in Europe … they projected an increase 100-fold over the next four decades

  14. Wild species / flora and fauna • Given that: • Climate is a primary driven of biotic system • Climate plays a central role in determining which types of species inhabit which parts of the world • The rate of warming is expected to continue to increase – increasing by a minimum of 1.1 to potentially 6.4 degrees C or more • Expectation is…

  15. What we know • Plants and animals survived the less-rapid warming of the post-Ice Age transition by shifting their ranges poleward and up in elevation, similar to the range shifts we have witnessed recently • Many species have begun to move – moving poleward; blooming earlier • What we have now • Rapid temperature change • In addition to everything else (such as?) • “the combined effects of rapid temperature increases and other anthropogenic changes collectively affect the flora and fauna of our planet more strongly – synergistically – than if each of these disturbances occurred alone.”

  16. Flora… • Thermal growing season (TGS) could be extended due to current warming • Why? • More days in the year in which plants can grow • Primary biological productivity increases • More carbon dioxide sequestered • More water consumption (in addition to more water consumption due to climate warming itself) • Water demand depends on water supply – may have more rainfall, or less, depending on region and locale

  17. Flora… • Consider a species that is on the border of its environmental range • One environmental factor may increase (temp) – does not mean that other environmental factors will increase (rain) to accommodate a species’ healthy growth • Even if more precipitation – still – expect more evaporation • In some places and for some species whose environment has changed, water availability could be a problem

  18. Alaskan White Spruce (Picea glauca) • Thermal growing season (TGS) extended due to current warming – yes • But – growth not increased • Why: temperature-induced drought stress • Interior of Alaska is semi-aird and in many places the potential ET = annual P • Increase potential ET through TGS and… • P. glauca is one of the most productive and widespread forest tree species in the boreal forest; plays important roe in northern-hemisphere terrestrial sink!

  19. Tropical-rainforest • A two decade long study (2004): of 18 tropical rainforest plots that were otherwise disturbed [study online] • All trees over 10 cm in DBH were tagged • Nearly 13,700 recorded • Analysis done on genus level (due to high diversity) • 244 genera – 115 used for statistical analysis • Within the plots, the rates of tree mortality, recruitment and growth have all increased • No increase in pioneer species • Increasing number of faster-growing trees • Decline in slower-growing trees • What is causing these changes?

  20. What is causing these changes? • Previous disturbance unlikely • Due to regional climate cycles – El-Nino related droughts which have increased over the last century? [two other analyses say no] • Rainfall changes (not drought) – i.e. decline in rainfall, river flow and ground water – also discounted and rejected • Accelerated forest productivity – due to increased carbon dioxide – or due to increased cloudiness and higher airborne nutrient transfer from increased forest fires (both climate-related factors) • Greenhouse gases the spur • These changes: local and global implications • Carbon sinks? – increases in carbon storage by tropical trees may be slowed by the tendency of canopy and emergent trees to produce wood of lower density as their size and growth rate increases

  21. Biological Dimension of Climatic-Change Fingerprint • What is a fingerprint • Fingerprints are changes that show a certain pattern that is unique to a specific climate-change driver. • [see online info from Pew Center on Global Climate Change] • Question: • Are there any general effects of current warming across natural systems? • Is it possible to discern a global-warming fingerprint?

  22. A biologist (Parmesan) and an economist (Yohe) studied this issue

  23. "A Globally Coherent Fingerprint of Climate Change Impacts across Natural Systems" Friday, January 31, 2003 GARY W. YOHE CAMILLE PARMESAN WESLEYAN UNIVERSITY UNIVERSITY OF TEXAS - AUSTIN

More Related