Projected distributions of novel and disappering climates by 2100 AD

Williamsm J.W., Jackson S.T., Kutzbach J.E., 2007, PNAS

Introduction

“Climate is primary control of distribution of species and ecosystem processes.”

Analysis of A2 and B1 scenario;GOAL: identification of region that will

experience:- High magnitude of local climate change- Novel climates- Disappearance of extant climates

Introduction – Methods – Results - Discussion

Niche Theory

Climatic Shift: locally changed, but still existing on earth.

Novel climate: a climate not yet present on earth

Disappearing climate: extant climate disappears.

Introduction – Methods – Results - Discussion

Niche Theory

Introduction – Methods – Results - Discussion

Species 1-3: several ecological responsesCommunity sp.1 & sp.3 disappearsCommunity sp. 1 & sp. 2 formingSpecies 4: Extinction

Methods and Results

• Simulation of mean June-Aug and Dec-Feb air temperature and precipitation using IPCC A2 and B1 emission scenarios for the end-

20th- and end-21st-century. • Interpolate simulations to a 2.8° by 2.8°grid.

• Calculation of Standard Euclidean Distance (SED) for the degree of dissimilarities between 20th and 21st century climate in each grid point.

Introduction – Methods – Results - Discussion

Methods

• Local change: High SED indicates large local climate change and integrated changes in temperature and precipitation

• Novel climates: Climatic distance (SED) between the end 21st century simulations for each grid point and its closest analog from the global pool of 20st century climates

• Disappearing climates: Climatic distance (SED) between the 20th century realization for each grid point and its closest 21st century climatic analog from the global pool

21st-century20th-century

Introduction – Methods – Results - Discussion

Local climate change

• Large changes everywhere in the A2 scenario• Larges changes in tropical and subtropical regions

Introduction – Methods – Results - Discussion

Novel future climates

• Clustering in tropical and subtropical regions scarcity in higher latitudes

• Highest dissimilarities over the Amazon and Indonesian Rainforest Projected poleward shift of thermal zones is a key determinant.

A2 B1

Introduction – Methods – Results - Discussion

Disappearance of extant climates

• Concentration in tropical mountains and poleward side of continents

A2 B1

Introduction – Methods – Results - Discussion

Consideration of dispersal limitation: pool of potential analogs is restricted to grid points within 500 km of each target grid point

Increased risk for species to experience the loss of extant or the occurrence of novel climateIntroduction – Methods – Results - Discussion

Risk of change in relation to global mean annual warming.

• Risk of novel and disappearing climates is linear to the magnitude of mean global warming

No obvious threshold for “dangerous” climate change

Introduction – Methods – Results - Discussion

Biodiversity Hotspots

http://www.nature.com/scitable/nated/content/5895/10.1038_403853a0-f1_large_2.jpgIntroduction – Methods – Results - Discussion

Biodiversity Hotspots

Introduction – Methods – Results - Discussion

Areas of disappearing climates closely overly hotspots

Disappearing Climates B1

Niche theory

http://ecuador.indymedia.org/images/2007/10/21985.jpg

Discussion

Introduction – Methods – Results - Discussion

A2 B1

Models predict: increased risk of fire and loss of forest cover in amazonia.

Discussion

• Tropical species are very sensitive.- temperatures vary little- small climatic range size

Discussion

Introduction – Methods – Results - Discussion

Forecasting species-level response is a challenge:Can they adapt? Can they migrate? What about interspecific differences in response time?

Conservation: dynamic networks of connected reserves?

Take home message

“Many current species and associations will be disrupted or disappear entirely.”