Dr Andy Reisinger, Senior Research Fellow, New Zealand Climate Change Research Institute, presents evidence that global warming, caused by human activity, is an irrefutable scientific fact; this is having huge ecological and social impacts which will ramify into future generations; were facing a global train wreck and have to act now.

1. Climate change:
overview and update
Andy Reisinger
Climate Change Research Institute
New Zealand Climate
Change Research Institute

2. Warming is unequivocal and widespread
• Global average atmospheric temperatures increasing
• Extreme temperatures increasing
• Ocean heat content increasing …
• … now directly linked to sea level rise
• Greenland and Antarctic Ice Sheets losing mass
• Unequivocal
Glaciers and snow cover declining
• Arctic sea ice extent decreasing
• Area of seasonally frozen ground decreasing
• Atmospheric water vapour content increasing
• More intense and longer droughts
• More frequent heavy precipitation events over land
• Tropical cyclone intensity increasing (in North Atlantic)
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3. Recent warming is due to greenhouse gases
Models reproduce
observed changes
only if we include the
warming effect of
greenhouse gases
Combination of
volcanic eruptions
and solar change
would have resulted
in small cooling over
the last 50 years
Figure source: IPCC WGI Figure SPM.4 3

4. Future warming depends on emissions
Figure source: based on IPCC WGI Figure SPM.5 and Third Assessment Report 4

5. Projected warming – does it matter?
Even at the lower end of future scenarios, the global
rate of change over the 21st century will almost
certainly be greater than experienced by human
civilisation over the past 10,000 years
Changes greater over land and more variable
We can no longer stop global warming, but reducing
emissions would reduce its rate and magnitude
Figure source: based IPCC WGI Figures 6.10 and Figure SPM.5 5

6. Global impacts of climate change
Source: IPCC WGII Table TS.5
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7. Settingemissions targets
reductions: policy
Stringent
450ppm CO2-eq
2° relative to pre-
C
industrial temperatures
Adaptation is necessary: Mitigation is necessary:
manage unavoidable change avoid unmanageable change
Source: IPCC WGII Table TS.5
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8. Global greenhouse gas emissions
Figure source: IPCC WGII Figure 1.1 8

9. Emissions reductions
• Each sector has options to reduce emissions
• The more we want to reduce emissions, the more
we have to include all sectors and all
opportunities
• Achieving emissions reductions requires:
• a price on emissions that makes the use of
alternative technologies attractive
• policies that support change in behaviour and the
development and deployment of new technologies
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10. Example electricity sector
Emissions of CO2 eventually have to reduce to zero to
stabilise greenhouse gas concentrations.
This requires research to develop new technologies,
reduce costs and increase feasibility/scale.
Figure: based on data from IPCC WGIII Figures 4.29, 4.30 and Tables 4.6, 6.7, 7.5 10

11. How does NZ compare? – income growth
35.00%
World
30.00% United States of America
European Union (27)
25.00% New Zealand
20.00%
15.00%
10.00%
5.00%
0.00%
1990 1992 1994 1996 1998 2000 2002 2004 2006
-5.00%
Income in purchasing power parity relative to 1990. Source: cait.wri.org 11

12. How does NZ compare? – CO2 emissions
70.00%
60.00% World
United States of America
European Union (27)
50.00%
New Zealand
40.00%
30.00%
20.00%
10.00%
0.00%
1990 1992 1994 1996 1998 2000 2002 2004 2006
-10.00%
Domestic CO2 emissions relative to 1990. Source: cait.wri.org 12

13. Scale of emissions reductions
• Stabilising concentrations at 450ppm CO2-eq:
• Developed countries reduce their emissions by 25-40% by
2020, and 80-95% by 2050, relative to 1990 emissions
• Developing countries reduce their emissions by 10-30%
below business-as-usual by 2020 and much more
substantial reductions by 2050. The most advanced
developing countries would need to do more.
• Stabilising concentrations at 450ppm CO2-eq gives
us only a 50/50 chance of not exceeding 2° !
C
• Delays or less stringent targets increase greenhouse
gas concentrations further and increase the risk of
serious and irreversible climate damages
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14. Latest updates
• Failure to make international progress would mean that we
are about to loose the chance to limit warming to 2°C.
• If everybody on the planet were allowed the same per capita
emissions, and we wish to limit global warming to 2° then
C,
New Zealanders will exhaust their emissions allowance
(even counting CO2 only !) by about 2020
• Polar ice sheets are loosing ice faster than predicted by ice
sheet models. Glaciers that drain the ice sheets are
accelerating with warming, leading to faster sea level rise.
• Recent studies suggest that sea level could rise by more
than 1m by 2100, and even 2m cannot be ruled out entirely
for scenarios without stringent emissions reductions
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