tuc, 21st october 2013 climate change – the scientific evidence and its implications why climate...
TRANSCRIPT
TUC, 21st October 2013
Climate change – the scientific evidence and its implications
Why climate change matters to us allJulia Slingo, Met Office Chief Scientist
TUC Green Growth conference 21 October 2013
Atmospheric Concentrations of Carbon Dioxide:
Crossing 400ppmv for the first time
© Crown copyright Met Office
Why 400ppmv is a big dealIce Core Records of Past Climate
Change
400
280
IPCC 4th and 5th Assessment Reports:Warming is unequivocal
‘Pauses’ in warming are expected and understood
Inter-Governmental Panel on Climate Change (2013)
Changes across the climate system are consistent with a warming world
Extremely likely (95-100%) that most of observed increase in global surface temperature since 1951 caused by human influence (IPCC 2013).
Assertion that we survived the Medieval Warm Period and Little Ice Age ignores the rapid increases in the world’s population and in the sophistication of our current civilisation.
Global Interdependencies: Circle of Securities
• Changing Exposure
– where we live
• Changing Vulnerability
– how we live
• Changing Climate
Climate Variability and ChangeUrbanisation
Population growth
Water
Economic
Food
Energy
Political
Health
• Report by UK and US scientists looking at extreme events in 2012
• Half of the extreme events studied displayed some evidence that human induced climate change was a contributing factor.
USA heatwave, spring 2012 Iberian drought, winter 2011/12 Arctic sea ice minimum, autumn 2012
New Zealand rainfall, winter 2011Australian rainfall, summer 2012 Inundation from Hurricane Sandy, autumn 2012
Increasing confidence that human emissions are increasing the risk of some types of
extreme events
Projections of future global warming
• Global warming >2˚C is likely for scenarios with little mitigation of emissions. No mitigation leads to a world more than 4˚C warmer than pre-industrial times
Inter-Governmental Panel on Climate Change (2013)
Projections of future sea level riseLong Term Commitment to Climate Change
• Global average sea level will rise during the 21st century; it is very likely that it will rise faster than it has during the last 40 years.
Inter-Governmental Panel on Climate Change (2013)
National Risk Register
A number of key national risks can be expected to increase
in likelihood and impact as a result of
climate change
‘Moving to the right’
Total CO2 emissions are strongly linked to total warming
If warming is to be limited to 2˚C, total CO2 emissions need to be limited to ~1000 Gigatonnes of Carbon (‘Trillionth Tonne’).
In conclusion...
Climate change is unequivocal. It is extremely likely that human influences have been the dominant cause of the observed warming since 1951. There is already evidence that climate change is leading to more extreme weather events that affect a world that is increasingly exposed, vulnerable and interdependentCurrent trajectories of carbon emissions take us towards a world 4˚C warmer than the present by the end of the centuryIf warming due to human emissions is to be limited to 2˚C, total emissions need to be limited to 1000 Gigatonnes of Carbon. About half of this has already been emitted.