Are we ready ? Our changing climate - Professor Mark Howden ANU Institute for Climate, Energy and Disaster Solutions Vice Chair, IPCC Working ...
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Are we ready ? Our changing climate. Professor Mark Howden ANU Institute for Climate, Energy and Disaster Solutions Vice Chair, IPCC Working Group II @ProfMarkHowden
CO2 emissions: record fall from COVID
2020
6.7%
CO2 fossil fuel emissions
decrease
(Gt CO2/year)
UPDATE
Year
Global Carbon Project 2020; Friedlingstein et al. 2020
Atmospheric GHGs: still breaking records
• CO2 today
418.7ppm
• Record levels of
methane and last
year highest
growth ever
• Record levels of
nitrous oxide
• Record levels of
other GHGs
NASA 2021, NOAA 2021
Globally – warming accelerating
• Equal warmest
Global mean temperature difference from
year on record
(1.24oC above
the pre-industrial
average)
1850-1900 (oC)
• 40% chance of
exceeding 1.5oC
at least once in
next 5 years
• Likely to breach
1.5oC by early
2030s
HADCRUT5; GISTEMP; NOAA; Berkeley Earth; WMO 2021
MDB: record temperatures
BoM 2021
Extremes almost everywhere, all the time
BoM 2021
Frost risk increasing in SE Australia
300
260
Day of last frost
(10th percentile)
220
180
-2 0 2
Screen minimum temperature (oC)
Howden et al. 2004, Crimp et al. 2016
MDB rainfall trends
• Declines across
most of the basin
• Particularly across
the high-yielding
upper catchments
BoM 2021
Change in pressure systems: Australia
BoM 2021
Change in pressure systems: Sthn hemisphere BoM 2021
Vapour pressure deficit (VPD) increasing
Yuan et al. 2019MDB flows: historical
MDBA 2020Climate changes dragging back farm profits
• Climate changes (post 2000)
affecting farm profits from
-37% (Vic.) to +8.7% (NT)
Hughes et al. 2020Climate changes drag back global ag productivity
• Global average agricultural productivity reduced by 21%
Ortiz-Bobea et al. 2021Choices about our future
Current
trajectory
2020 Estimate
Paris Agreement
commitments
2oC
1.5oC
Global Carbon Project 2018Temperature projections
Daytime Night-time
Low emissions
High emissions
IPCC 2013Climate reduces total water storage
In this region too:
• Proportionally
more summer rain
• Higher rainfall
intensity
• Increased season
to season
variability
• Increased potential
evaporation
Pokhrel et al. 2021MDB flows: historical and projected
2030 2050 2080
MDBA 2020; CSIRO 2021Drought becomes much worse: global
• Food prices likely
to increase
• Food trade
increase due to
variability in supply
• Competitive
advantage to those
who adapt best
Pokhrel et al. 2021Unlikely to achieve the Paris Agreement goals
• On current trends, the probability of staying below 2°C of
warming is only 5%
• But if all countries meet their nationally determined
contributions and continue to reduce emissions at the same
rate after 2030, it rises to 26%
• For a given temperature goal, the time to net zero is not fixed
– stronger interim targets push out the net-zero date and vice
versa
• Strong rationale for increasing adaptation action
• Many opportunities in the regions in emission-reduction
Liu and Raftery 2021Key messages
• The evidence of climate change
Reconfiguring: your and
goalsitsand
impacts keeps
resources
accumulating and the news is not good
• Future projections look worse the more we know
• Rapid and substantial action is needed and is publically supported
• We all have roles to play - togetherThank you Prof Mark Howden ANU Institute for Climate, Energy and Disaster Solutions mark.howden@anu.edu.au @ProfMarkHowden +61 2 6125 7266 Vice Chair, IPCC Working Group II
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