Are 70% of Species Really Endangered by Climate Change? Craig Loehle NCASI ICCC Las Vegas.

Are 70% of Species Really Endangered by Climate Change?

Craig LoehleNCASI

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 climate2. Regional models downscale output3. Bioclimate envelope models developed4. Compare current and forecast species range5. Change too rapid for migration6. 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].

10 15 20 25 300

2

4

6

8

10

12

grow

th

°C

Implicit model

actual

TEMPERATURE TOLERANCE

• Rising CO2 increases temperature tolerance (and drought tolerance) and raises peak temperature curve

0 1 2 3 40

1

2

3

4

5

NP

P

temperature

TEMPERATURE TOLERANCE

• Greenhouse/FACE studies– Rising CO2 and temperature give rising NPP (17% to

28%)– Even 14°C rise from ambient for northern trees– Dozens of studies

• Simulation Models– If include CO2 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