ipcc fifth assessment report synthesis report · ipcc ar5 synthesis report adaptation to climate...

IPCC AR5 Synthesis Report

IPCC Fifth Assessment Report

Synthesis Report Jan Fuglestvedt, CICERO

Karen O’Brien, University of Oslo

Working Group I WGI

Working Group II WGII

Working Group III WGIII

Synthesis Report

Bredt og åpent internasjonalt samarbeid


AR5 SYR SPM

More recent data (1970-2010) and other gases than CO2

What factors have driven emission changes?


Sources of emissions

Energy production remains the primary sources of GHG emissions

35% 24% 21% 14%

6.4%

2010 GHG emissions

Energy Sector

Agriculture,

forests and

other land uses

Industry Transport

Building

Sector

AR5 WGIII SPM


Causes of climate change

Causes of climate change

Anthropogenic greenhouse gas emissions have

increased since the pre-industrial era, driven

largely by economic and population growth, and

are now higher than ever.

Their effects, together with those of other

anthropogenic drivers, have been detected

throughout the climate system and are extremely

likely to have been the dominant cause of the

observed warming since the mid-20th century.


Impacts are already underway

• Tropics to the poles

• On all continents and in the ocean

• Affecting rich and poor countries

AR5 WGII SPM


Some of the changes in extreme weather and climate events

observed since about 1950 have been linked to human influence

AR5 WGI SPM


What is happening in Norway?


What about the future?


Projected climate changes

Continued emissions of greenhouse gases will cause

further warming and changes in the climate system

AR5 WGI SPM


Projected climate changes

Continued emissions of greenhouse gases will cause

further warming and changes in the climate system

Global glacier volume will further decrease

Global mean sea level will continue to rise during the 21st century

It is very likely that the Arctic sea ice cover will continue to shrink and thin as global mean surface temperature rises

Oceans will continue to warm during the 21st century

Ocean acidification will continue.


Potential Impacts of Climate Change

• Risk of severe ill-health and disrupted livelihoods;

• Systemic risks due to extreme weather events;

• Risk of loss of ecosystems, biodiversity, and

ecosystem goods, functions and services;

• Risk of food and water insecurity. AR5 WGII SPM


Climate Change Poses Risk for Food Production

AR5 SYR SPM


Adaptation to climate change

Adaptation can reduce the risks of climate change

impacts, but there are limits to its effectiveness.

Some adaptation responses involve significant

co-benefits, synergies, and trade-offs.

Increasing climate change will increase

challenges for many adaptation options.

AR5 WGI SPM, AR5 WGII SPM,AR5 WGIII SPM


We need both adaptation and mitigation

AR5 WGIII SPM

Effective adaptation and mitigation responses will depend on policies and measures across multiple scales: regional, national and sub-national.

Adaptation and mitigation responses are underpinned by common enabling factors


Limiting Temperature Increase to 2˚C

Measures exist to achieve the substantial emissions

reductions required to limit likely warming to 2°C

Implementing reductions in GHG emissions poses

substantial technological, economic, social, and

institutional challenges

But delaying mitigation will substantially increase the

challenges associated with limiting warming to 2°C

AR5 WGI SPM, AR5 WGII SPM,AR5 WGIII SPM


Mitigation Measures

More efficient use of energy

Greater use of low-carbon and no-carbon energy • Many of these technologies exist today

Improved carbon sinks • Reduced deforestation and improved forest management

and planting of new forests

• Bio-energy with carbon capture and storage

Lifestyle and behavioural changes AR5 WGIII SPM

RCPs

This assumes that there will be no major volcanic eruptions or changes in some natural sources (e.g., CH4 and N2O), or unexpected changes in total solar irradiance.


The Choices We Make Will Create Different Outcomes

With substantial

mitigation

Without additional

mitigation

Change in average surface temperature (1986–2005 to 2081–2100) AR5 WGI SPM


Stabilization of atmospheric concentrations requires moving away from the baseline – regardless of the mitigation goal.

AR5 WGIII SPM


Stabilization of atmospheric concentrations requires moving away from the baseline – regardless of the mitigation goal.

~3°C

AR5 WGIII SPM

Key characteristics of the scenarios collected and assessed for WGIII

Delaying mitigation increases the difficulty and narrows the options for limiting warming to 2°C.

„immediate action“

Delaying mitigation increases the difficulty and narrows the options for limiting warming to 2°C.

Delaying mitigation is estimated to increase the difficulty and narrow the options for limiting warming to 2°C.

„immediate action“

„delayed mitigation“


Based on Figures 6.32 and 7.16


Implications for sustainable development

➜ Climate change is a threat to equitable

and sustainable development

➜ Strategies and actions can be pursued

now that will move towards climate-resilient

pathways for sustainable development

➜ at the same time helping to improve livelihoods, social and economic well-being, and effective environmental management.

AR5 WGI SPM, AR5 WGII SPM

The window for action is rapidly closing

65% of our carbon budget compatible with a 2°C goal already used

Amount Used

1870-2011:

515 GtC

Amount

Remaining:

275 GtC

Total Carbon

Budget:

790 GtC

Fossil carbon reserves exceed this remaining budget by a factor of 4 to 7, with resources much larger still.


Synthesis is essential !

AR5 WGIII SPM

A combination of adaptation and substantial, sustained reductions in

greenhouse gas emissions can limit climate change risks

The risks from climate change, assessed by the WGII of the IPCC AR5, and aggregated in five “Reasons for Concerns”

Levels of risk across the Reasons for Concern can be associated with

a level of global temperature change.

Here shown for a warming by 2oC

The link between cumulative CO2 emissions and global mean temperature

The pink plume is from WGI complex models.

It includes the uncertainty from non-CO2 gases and climate and carbon cycle uncertainty, using the likely

range

Levels of risks can be connected to cumulative CO2 emission levels, for the average climate response, for high climate sensitivity (lower cumulative emissions), and for low climate

sensitivity (higher cumulative emissions)

Høy klima-følsomhet

Lav klima-følsomhet

The link between changes in annual GHG emissions by 2050

and the cumulative CO2 emissions by 2100 of the WGIII

scenario categories



Levels of risks can now be connected to GHG emission changes by 2050.

Added uncertainty arises from action on non-CO2 gases, timing of pre-2050 action, and ambition of

post-2050 action.



The constraint on changes in GHG emissions by 2050 depends on the sensitivity of the climate response.

Here, with large climate sensitivity



The constraint on changes in GHG emissions by 2050 depends on the sensitivity of the climate response.

Here, with low climate sensitivity




Take home messages

➜ Human influence on the climate system is clear

➜ Observed impacts are visible in all parts of the world

➜ The more we delay our responses the greater the risk

of severe, widespread and irreversible impacts; and

the greater the costs

➜ We have the options to limit climate change and build

a more prosperous, sustainable future

The report is a comprehensive map for policy makers

What does the SYR mean for the path ahead?

Policy relevant but not policy prescriptive

IPCC does not give recommendations.

But there is one thing we would like to

recommend:

Read the report!


IPCC Fifth Assessment Report

Synthesis Report

ipcc fifth assessment report synthesis report · ipcc ar5 synthesis report adaptation to climate...

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