Working Group 2Findings from AR4

Expectations from AR5

Chris FieldVicente Barros

Co-chairs, IPCC WG2

8 December 2009

WG 2 – AR 4: Themes• Vast stock of examples of observed changes• Wide array of projected future impacts

– Magnitude varies with scenario– Damages concentrated in extreme events

• Vulnerability exacerbated by other stresses– Hot spots– Vulnerable sectors and populations in all regions

• Many impacts can be avoided, reduced, or delayed by mitigation

• Increased adaptation can help reduce future vulnerability

Observed impacts• Physical and biological systems• 29,000 time series in chapter 1• All continents and most oceans• Likely that AGW has had a discernable influence

AR4, WG2, Fig 14.1

Changes in physical and biological systems, 1970-2004:Statistical support for human influence.

AR4, WG2, Fig TS 1

Advanced detection-attribution techniques to test link between species movements and AGW

AR4, WG2, Box TS 4

Responses to earlier springs• Average advance in signs of

spring: 2.3 days/decade– Budburst, flowering, nesting,

fledging, etc.– 172 species (trees, shrubs,

herbs, butterflies, birds, amphibians, fish

• Parmesan & Yohe 2003 Nature v 421 p 37

• Advancing bud-burst date: – 2.5 days/decade– 1900-1998– Aspen in Edmonton

• Beaubien & Freedland. 2000. Int J. Meteorol.

Impacts: links to specific levels of climate change

AR4, WG2, Table TS 3

Threats to water security

AR4, WG2, Fig TS 5

Regional threats: Australia and New Zealand

AR4, WG2, Fig TS 12

Avoiding impactswith mitigation

AR4, WG2, Fig TS 4

Managing vulnerability with adaptation and mitigation

AR4, WG2, Fig TS 19adaptation

mit

igat

ion

WG2 in the AR5• Common frameworks & currencies for impacts,

adaptation, and mitigation• Broadening the range of assessed impacts• The interaction of climate change & development• Integrating climate science with climate impacts• Assessing new impact studies based on AR5 climate• Improving the treatment of regional aspects of

climate change

AR5: Broader range of assessed impacts

Ocean impacts

• Oceans– half of global NPP– 70% of surface area– 41% has multiple

impacts

Behrenfeld et al Nature 2006

AR5:Improved

treatment of extremes and

disasters

AR4, WG2, Fig TS 13

AR5:More thorough treatment of costs of climate change:

common framework & more inclusive currencies

IPCC 2007

IPCC AR5

• Move from “it’s real” to “here is the information you need to make good decisions for your stakeholders”– Risk management framing– Multiple stresses framing– Full partnership for adaptation