Presentation on theme: "Are 70% of Species Really Endangered by Climate Change? Craig Loehle NCASI ICCC Las Vegas."— Presentation transcript:
Are 70% of Species Really Endangered by Climate Change? Craig Loehle NCASI ICCC Las Vegas
THE PROBLEM Claim: Rapid warming will cause climate zones to shift too fast Result: – Risk of mass extinctions – State plans for massive migration corridors (e.g., WI) – Using climate change to justify listing species as endangered
THE BASIS 1.Climate model projects future climate 2.Regional models downscale output 3.Bioclimate envelope models developed 4.Compare current and forecast species range 5.Change too rapid for migration 6.Predict 20-70% of species at risk
CLIMATE MODEL ISSUES Climate models differ from each other All models are running hot The hottest models (6 deg warming) are often used for these exercises (increases impact)
Models vs. observations (from Roy Spencer’s blog)
Assumption underlying extinction risk claims is that species bioclimate zones will shift in the next few decades. In the cross-hatched zones, the species will perish. If there is no overlap, extinction will occur. new range old range dieback zone
BUT TREES CAN TOLERATE HEAT Northern trees are there because of frost tolerance that trades off against growth rate ALL Canadian species grow in botanical gardens in Australia Lethal temperature for tropical & northern plants is the same (45 deg C)
Example range of boreal species (Abies balsamea) compared to locations where it is found in botanical gardens. Abies in Virginia and West Virginia (small gray circles) are located at higher elevations.
Bioclimate models mischaracterize niche based on static correlation [competition narrows realized niche]. growth °C°C Implicit model actual
TEMPERATURE TOLERANCE Rising CO 2 increases temperature tolerance (and drought tolerance) and raises peak temperature curve NPP temperature
TEMPERATURE TOLERANCE Greenhouse/FACE studies – Rising CO 2 and temperature give rising NPP (17% to 28%) – Even 14°C rise from ambient for northern trees – Dozens of studies Simulation Models – If include CO 2 predict more growth – Lake States simulation 2X forest growth – No massive range shifts – Contradict range shift idea
NET TEMPERATURE RESPONSE Increased primary productivity (observed in satellite data) Increased drought tolerance (inferred from satellite data) No dieback No extinctions (animals also), esp not 20-75% – (New IPCC rept admits no extinctions to date) Slow northward tree migration – Hundreds or thousands of years
IPCC and Geographic Range AR5 admits no trailing edge die-offs AR5 and especially NCA play up northward migrations BUT observed range shifts are very small and NOT universal No way to get high extinctions from these facts
True Extinction Causes 95% bird & mammal extinctions past 200 yrs from islands Water pollution Habitat loss Hunting Listing all species as endangered & building corridors are useless activites
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