Transcript Climate Change: Reality & Future

The Earth in 2050.
Climate change – will humanity follow the
Polar Bear and the Great Barrier Reef?
Global Warming
– the measurements
Global surface air temperature
Pattern of change
Local
Change
Sheffield annual mean temperature
10
9
annual meant
8
7
18
83
18
93
19
03
19
13
19
24
19
34
19
44
19
54
19
65
19
75
19
85
19
95
temperature (C)
11
year
No data
Global Warming
– context over last 1000
years
Global surface air temperature
reconstructions over the last
millennium
…. And longer
Other
changes
Arctic sea-ice extent
The Climate
System
The Climate
System
(Naturally)
The Climate
System
(anthropogenically)
Solar variability
Relative
Sunspot
number
Solar
Constant
(scaled to
satellite
observation
)
Volcanic Record from
Greenland Ice Core
Atmospheric gases
Monthly average atmospheric
CO2 (Mauna Loa observatory,
Hawaii)
Monthly average values of
atmospheric methane,
California
The Greenhouse Effect
Land Cover
Post-glacial
maximum
forest cover (similar
to pre-industrial)
Current forest cover
Model “hindcast” of climate
change since 1890
Primary Energy Consumption
(kW/person)
100
Norway
10
Russia
UK
1
China
USA
France
Brazil
India
0.1
0.01
100
1000
10000
100000
GDP ($/person/year)
Wealth and energy consumption are related- as individuals
get richer their lifestyles have increased energy demand.
Future Global
Temperature?
Future Global
Temperature?
And
Rainfall
Future Global
Temperature?
A2
B2
Future Global
Temperature?
Scenario CO2
Even eventual CO2 decreases lead to global warming
The regional picture in
2070-2100 compared to
1961-90
Annual mean temperature change averaged across all models
(colour;oC)
Range of uncertainty (blue line; oC)
Range/(standard deviation) (green)
Polar Bears in 2050?
• Depend on sea-ice for
hunting seals and land
for winter dens
• There could be no
summer sea-ice by
2050
• Interval of post-den
starvation gets longer –
is it sustainable?
Great Barrier Reef in 2050?
• Major bleachings (coral
dieback) have occurred
every few years during
periods of high sea
temperature
• A permanent temperature
rise of 1-2oC could kill the
coral permanently
2002
The UK in 2100?
• Very Likely ~ 2-4oC warmer
• Very Likely 2-7% wetter, concentrated in
stormier autumn and winter
• Very Likely a sea level rise of 0.11-0.77 m
• Very Likely a rise in oceanic pH
• But less warming than similar latitudes in the
Northern Hemisphere because of a predicted
slowdown in the Gulf Stream, which has a very
small probability of being abrupt
• Global warming at the end of the last
glaciation was the spark for civilisation
• But facing unprecedentedly rapid change,
with a global population perhaps 1000
times greater
• Predictions will improve – next IPCC
report out this month!
• But some change is now inevitable so the
challenge is to mitigate change and adapt