1 / 52

Climate Change

Climate Change Climate Change In the last 90 years the Earth’s mean temp rose 0.6 o C, a rate not seen in 10K yrs The scientific facts are clear and the vast majority of climatic scientists have determined that the major cause is anthropogenically produced greenhouses

ostinmannual
Download Presentation

Climate Change

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. Climate Change

  2. Climate Change • In the last 90 years the Earth’s mean temp rose 0.6oC, a rate not seen in 10K yrs • The scientific facts are clear and the vast majority of climatic scientists have determined that the major cause is anthropogenically produced greenhouses (but don’t call global warming)

  3. Climate Change • However, the most influential discussions are in the policy and public arenas • What does anthropogenic climate change signify for the future? • Is climate change reversible? • How quickly will weather patterns change? • What can be done to mitigate the detrimental effect of altered climates? • How will new climatic patterns influence species’ distributions and biodiversity?

  4. The Nature of Climate Change • Generally, climate shifts have been caused by changes in retention and distribution of solar energy across the planet • Solar radiation passes through the atmosphere as short wavelength ultraviolet (UV) wavs

  5. Climate Change • Fig 10.1

  6. The Nature of Climate Change • The most important gases in the energy balance are CO2, CH4, and H2O as these cannot be penetrated by radiation in the infrared spectrum (long-wave) • These ‘greenhouse’ gases keep the earth approximately 60oC warmer than would be expected without them

  7. Climate Change through Time • Since the industrial revolution, burning fossil fuels has increased greenhouse gases by about 30% • However, we know there is always variation in systems • Historically, we have been cooling since the Tertiary period (50-60MYA)..10oC

  8. Climate Change through Time • Average global temperature over last 65MY. Gray indicate hotter than current, black cooler. Note from 2MYA to 12KYA strong cycles

  9. Climate Change through Time • Looking at a finer time scale we can see fluctuations throughout the Pleistocene (1.8MYA to 12KYA) • The Milankovitch cycles match the Earth’s orbit and tilt relative to the sun and drives the temperature cycle through a series of positive and negative feedbacks

  10. Climate Change through Time • Small bubbles trapped in ice of Antarctica yield info on atmospheric composition • Furthermore, ration of 18O2 to 16O2 can accurately record temperature • This approach has yielded a relatively accurate temperature history going back 740KYA

  11. Climate Change through Time • Relationship between temperature and CO2 over past 160K yrs. • Note the current elevated CO2 levels

  12. Climate Change through Time • It is important to remember the impact of relatively small changes • E.g. peak glacial periods were only about 5oC cooler than current temperatures • Our current warming trend will push it to one warmer than was ever experienced during the Pleistocene period

  13. Human Enhancement of Greenhouse Effect • The insulating properties of CO2 were discovered in the mid-1800’s • CO2 has rose 36% since 1910, which is well outside historical ranges

  14. Current and Future Climate and Change • Scientists have developed a series of global climate models (GCMs) based upon the processes by which atmospheric greenhouse gases affect global climate • The models vary based upon different rates of gas emission (what affects rate?) • All models suggest warming should be greatest at the poles, least in the tropics

  15. Current and Future Climate and Change • E.g. in some parts of AL, Canada and Siberia mean annual has risen 2-4oC since 1900 • Another pattern is the lack of nights below freezing in the mid-latitudes (fig 10.6) • Another pattern is the change is precipitation (especially in intensity), but again, not consistent everywhere

  16. Current and Future Climate and Change • Black indicates warming and gray indicates cooling • Size indicates magnitude of change

  17. Current and Future Climate and Change • Black is wetter and gray is drier • Size indicates magnitude of change

  18. Current and Future Climate and Change • Ironically, the GCMs all suggest continued increase in precipitation, but with warmer climate, evapotranspiration is increased • Furthermore, the variance in precipitation events gets larger • What is the impact of larger variances but not means?

  19. Oceans: Sea Level and Circulation • Is beach front property consistent? • 20KYA, sea levels were as much as 120m lower than current levels • Annual changes are relatively small (e.g. 0.1-0.2mm) over past 3K yrs • However, past 200 yrs there has been rapid rising of ocean levels due to two factors: precip, ice caps (.2-.4mm) and thermal expansion (1mm annually)

  20. Oceans: Sea Level and Circulation • Sea levels rise over 3K yrs in 3 Euro cities

  21. Oceans: Sea Level and Circulation • Major ocean circulation systems are already showing signs of being affected by the rise in atmospheric temperatures • El Niño (and La Niña) events have increased in frequently and intensity (warming of mid-Pacific, pushing into cold waters) • Some models predict by 2050 “normal” years will resemble current El Niño yrs

  22. Oceans: Sea Level and Circulation • Warm H2O surges in cold water areas

  23. Oceans: Sea Level and Circulation • Snow, Ice, and Hydrological changes • Widespread retreat of glaciers in N & S Am, NZ, Af, Europe and Asia • (e.g. GNP, 70% glaciers lost…gone 2020) • (e.g. Mt Kilimanjaro 60%) • Approximately 30% of projected sea change will come from glacial melt

  24. Oceans: Sea Level and Circulation • Another problem is flood events rather than water soaking into the soil • In many areas, H2O comes in the form of snowfall with gradual melting feeding streams/rivers throughout summer • Spring melts are occurring earlier

  25. Oceans: Sea Level and Circulation • Glacial retreat (1973 and 2000)

  26. Predicted Biological Impacts • So many biological processes are tied to climatic events, the idea that these will change may have profound impacts • One approach to better understand the potential impact is to identify species’ distributions and their ‘climate envelope” from manipulative studies • For an in-depth look, Case Study 10.1

  27. Predicted Biological Impacts • A simplistic view of biotic responses is that species may simply alter their distribution quickly (e.g. birds) or gradually (e.g. seed dispersal) • Paleoecologists have found many communities found together no longer co-occur • Why?

  28. Predicted Biological Impactsextreme weather • Many systems are strongly influenced by climate and weather extremes • E.g. frost boundaries and plants • E.g. precipitation limits animals & plants • Drought in NM in 1950’s, pine and p-j, 2km • 9-banded armadillo, 39cm and <24 freezes • Single events can have long-term affects • Drought and Darwin’s finches • Warm water events, bleach coral reefs

  29. Predicted Biological Impacts • Prolonged climate swings can impact • Map turtles; 28oC<M and >30oC F • Many insect populations boom/bust with climatic events • Host-parasite and infectious diseases are strongly influenced by climate • Even if extremes don’t increase, their frequency may increase

  30. Predicted Biological Impacts • Increases in mean temperature, leading to more record temperatures

  31. Observed Biological Impacts • An increase in both mean and variance temperatures

  32. Observed Biological Impacts • Detection and Attribution • It is extremely important to determine the relative impact of climate change • Won’t review the evidence on CC • Studies examining the impact of CC on wildlife are by nature, correlative rather than experimental (FACE-free air CO2 Exchange) • Attribution now a priority for many

  33. Observed Biological Impacts • Evolutionary & Morphological Changes • Because of the rapid nature of CC, little discussion of evolutionary adaptations • Drosophila subobscura from N Euro had longer wings than S, 20 yrs adjusted to the climate envelop (more similar to S Euro) • E.g. Desert rodents have gotten 16% smaller body size… why?

  34. Observed Biological Impacts • Phenological Shifts (e.g. amount of daylight, seasonal weather) in organisms (e.g. arrival of migratory birds) • Many biological events are temp driven (e.g. leaf emergence, turtle hatching) • E.g. in AZ, MEJA hatch 10 days (’71 to ’98) • Many other examples (ice out, spring bloom) • European amphibian breeding advanced • There can be desynchronization…BTBW

  35. Abundance Change and Community Reassembly • Climate can have a direct impact on populations and communities • E.g. BTBW and El Niño (S) and La Niña (W) • Community structure has been changed • In CA waters, warming waters have favored a different plant community

  36. Abundance Change and Community Reassembly • Mean annual ocean temperatures at Scripps

  37. Abundance Change and Community Reassembly • Southern species have increased in abundance while Northern species have decreased in S CA

  38. Abundance Change and Community Reassembly • In terrestrial communities, there has been woody incursion into grasslands • In experimental communities, increases in temp, H2O, and CO2, all result in increases in woody species

  39. Range Shifts • Species ranges are dynamic, changing both spatially and temporally

  40. Range Shifts • There are many examples of range shifts in apparent direct response to CC • In N Am and Europe, 2/3 of butterflies (n=58) studied have shifted N by 100km per decade • Montane studies have shown plants and animals are being found at higher elevations

  41. Range Shifts • Patterns of population extinction of Edith’s checkerspot butterfly Eupydryas editha from 1860 to 1996 • Note significantly higher extinction in N • Black present, gray extinct

  42. Range Shifts • Overwintering range of the sachem skipper butterfly, which is limited by repeated to exposures to -4oC

  43. Synthesis of Impacts • Is there a bias in our conclusions about the impact of CC? “positive publishing” • A meta-study (1700 sp), about ½ the sp were stable • However, 50% exhibited significant responses to regional warming (e.g. phenology or distributional shifts) • Table 10.1

  44. Conservation Implications of CCExtinctions • There has been a spike in extinctions in recent centuries • There have only been 2 extinctions directly attributable to CC (2 trop frog) • Abundance of zooplankton off CA has declined by 80%...and sp relying on this food base are in trouble

  45. Conservation Implications of CCExtinctions • The ability to track changes is important for species’ survival • Unfortunately, many endangered sp tend to have such traits (e.g. limited dispersal, small ranges, strong local adaptation) • Constructing a ‘climate envelope’ of threshold values (of precip and temp) can help predict impacts of species

  46. Conservation Implications of CCExtinctions • Range shift model of a S Af plant

  47. Conservation Implications of CCExtinctions • A synthesis study of extinction risk estimates suggests a rough estimate of extinctions by 2050 • With perfect dispersal and minimal reduction in climate envelope, ranges from about 9-13% of sp would go extinct (1.2oC) to 21-32% (2oC) • Note: these estimates are strictly climate-based. Other problems?

  48. Responses to CC by Managers • Most managers and conservation planners focus on local-scale projects • Climate shifts cause problems for locals because they don’t account for climate • Consequently, they need climate models that are not only accurate, but at a spatial scale relevant to locals

  49. Responses to CC by Managers • There are adaptive approaches managers could use • Susceptibility analysis of impact of CC • Design/adjust reserve to allow movement • Promote corridors • Create dynamic habitat conservation plans • Alleviate nonclimate stressors • Generalization of climate prediction models

More Related