Transcript Debunking the myths of Climate Change

Debunking the myths of
Climate Change
Helen Young
Former Lead Presenter
BBC Weather Centre
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CLIMATE CHANGE:- A HOT TOPIC
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CLIMATE CHANGE:- IN THE MEDIA
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CLIMATE CHANGE:- weather events
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WEATHER and CLIMATE
Weather – instantaneous atmospheric conditions temperature, rainfall, pressure, wind etc
Climate - the long-term signal derived from individual
weather events.
‘Averaged out’ weather over a long period of time.
- Climate scientists normally use a period of 30 years
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WEATHER 1990ish
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WEATHER 2005ish
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CLIMATE CHANGE:- A GLOBAL ISSUE
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SCIENTIFIC COMMUNITIES- IPCC
Recognizing the problem of potential global climate change,
the World Meteorological Organization (WMO) and the United
Nations Environment Programme (UNEP) established the
Intergovernmental Panel on Climate Change (IPCC) in
1988. It is open to all members of the UN and WMO.
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NATURE
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Changes in Met Office Computing
1981
The Met Office’s first Super Computer!
Changes in Met Office Computing
2003
Arrival of NEC SX-6, One of the Worlds Fastest Supercomputers
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Changes in Met Office Computing
Ferranti Mercury - ‘Meteor’
3000 calculations per second
The ‘Cray twins’
160,000 million calculations per second
The NEC SX-6 computer installed Exeter 2004,
6 times more powerful
2005, 2 million, million calculations per second
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Numerical Model Accuracy
Area: North Atlantic
0
New model
introduced
New model
introduced
New model
introduced
2
24-hr forecast
RMS MSLP
4
48-hr forecast
6
72-hr forecast
8
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20
00
19
96
19
90
19
80
19
70
10
Myth 1
Our climate has always changed, this is just another
natural change and nothing to do with humans.
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Grape vines
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Three Cranes Wharf near Blackfriars in the City
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CLIMATE 1000 - 2000AD
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Source: IPCC 2000
How much climate change has there really been?
GLOBAL TEMPERATURES have risen by about 0.7ºC between 1861 and 2003
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Observed and simulated change
Natural factors
1.0
Temperature change ºC
observed
observed
model
modelsimulation
simulation
+
0.5
0.0
-0.5
1850
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1900
1950
2000
THE GREENHOUSE EFFECT
..most escapes to outer space
and cools the earth...
SUN
…but some IR is trapped by
some gases in the air, thus
reducing the cooling.
Sunlight
passes
through the
atmosphere..
..and warms the earth.
Infra-red radiation
is given off by the earth...
GREENHOUSE GASES
The most important greenhouse gases are:carbon dioxide
methane
nitrous oxide
hydrofluorocarbons
Perfluorocarbons
sulphur hexafluoride.
These are the gases that are covered by the Kyoto Protocol.
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are
also powerful greenhouse gases but they are being progressively phased
out under the Montreal Protocol as they also damage the stratospheric
ozone layer.
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HUMAN ACTIVITIES HAVE CHANGED THE ATMOSPHERE
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CO2 Concentration in Ice Core Samples and
Projections for Next 100 Years
Projected (2100)
700
Projected
(2100)
650
Vostok Record
IPCC IS92a Scenario
Law Dome Record
Mauna Loa Record
550
500
450
400
Current
Current
(2001)
(2005)
350
300
250
200
150
400,000
300,000
200,000
Years Before Present
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(B.P. -- 1950)
100,000
0
(ppmv)
2 Concentration
CO2CO
Concentration
(ppmv)
600
Myth 2
Carbon dioxide is not driving our current warming.
Carbon Dioxide only makes up a small part of the
atmosphere therefore it cannot be responsible for this
current Global Warming.
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EARTH’S ORBIT
Orbit for Northern Hemisphere
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CO2 concentrations have risen by over 30% due to human activities
Projected levels of atmospheric CO2 during the
in Ice Core Samples and
next 100 years wouldCObeConcentration
higher than
at anytime
Projections for Next 100 Years
in the last 440,000 yrs
Projected (2100)
2
700
Projected
(2100)
650
Vostok Record
IPCC IS92a Scenario
Law Dome Record
Mauna Loa Record
550
500
450
400
Current
(2001)
Current (2007)
350
300
250
200
150
400,000
300,000
200,000
Years Before Present
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(B.P. -- 1950)
100,000
0
CO2CO
Concentration
(ppmv)
2 Concentration (ppmv)
600
CO2 concentrations have risen by over 30% due to human activities
Projected levels of atmospheric CO2 during the
in Ice Core Samples and
next 100 years would CO
beConcentration
higher
than
at anytime
Projections for Next 100 Years
in the last 440,000 yrs
Projected (2100)
2
700
Projected
(2100)
650
Vostok Record
IPCC IS92a Scenario
Law Dome Record
Mauna Loa Record
550
500
450
400
Current
Current
(2001)
(2005)
350
300
250
200
150
400,000
300,000
200,000
Years Before Present
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(B.P. -- 1950)
100,000
0
(ppmv)
2 Concentration
CO2CO
Concentration
(ppmv)
600
Observed and simulated change
1.0
Natural & man-made factors
Temperature change ºC
observed
observed
model
modelsimulation
simulation
+
0.5
+
0.0
-0.5
1850
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1900
1950
2000
RELATIVE WARMING OF GREENHOUSE GASES
current emissions, effect over next 100 years
Methane
24%
Nitrous
oxide 10%
Others
3%
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Carbon
dioxide
63%
ATMOSPHERIC CONSTITUENTS which affect climate;
sources and lifetimes
Carbon dioxide
Fossil fuels, deforestation
100 years
Methane
Agriculture, natural gas
10 years
Other gases
(nitrous oxide, CFCs, ground-level ozone..)
Aerosols
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Power generation, transport
2 weeks
CARBON DIOXIDE (CO2)
 The most important man-made greenhouse gas
 About half of the CO2 emitted by Man remains in the
atmosphere; remainder absorbed by vegetation and
oceans
 CO2 risen by 1/3 since the industrial revolution
 CO2 emissions would have to be reduced by about 70%
to stabilise climate change
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Myth 3
Computer models are unreliable.
How can you predict 100 years ahead when you can’t
predict the weather for the next 5 days?
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THE CLIMATE SYSTEM
ATMOSPHERE
Terrestrial
radiation
Greenhouse gases and aerosol
Ice- sheets
snow
Clouds
Solar
radiation
Precipitation
Sea-ice
OCEAN
Biomass
LAND
Development of Hadley Centre Climate Models
ATMOSPHERE
LAND OCEAN ICE SULPHUR
CARBON
1999 ATMOSPHERE
LAND OCEAN ICE SULPHUR
CARBON
1997 ATMOSPHERE
LAND OCEAN ICE SULPHUR
1992 ATMOSPHERE
LAND OCEAN ICE
ATMOSPHERE
1985 ATMOSPHERE
1960s ATMOSPHERE
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LAND OCEAN
LAND
CHEMISTRY
Projections of Climate Change
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Model Projections – Global temperature rise
Global temperature rise, degrees C
High emissions
Medium-high emissions
Medium-low emissions
Low emissions
Start to diverge
from mid-century
Other climate
models:
1.5 - 6°C
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Myth 4
It’s all to do with the sunThere’s a strong link between increasing temperatures
on earth and the number of sunspots on the sun.
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Solar influence
Temperature anomaly relative to late 19th century.
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GJJ1999
CHANGES IN SOLAR ENERGY
Solar radiation / W m–2
1374
1372
1370
1368
1850
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1900
1950
2000
Myth 6
The NAD will be cut off and we’ll be heading for another
ice age
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GJJ1999
GLOBAL OCEAN CIRCULATION
COOLING
WARM
SURFACE
CURRENT
INTERMEDIATE
WATERS
WARM AND LESS SALINE
ANTARCTIC CIRCUMPOLAR CURRENT
The Gulf Stream
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Circulation strength
NORTH ATLANTIC OCEAN CIRCULATION
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No change
SRES A1FI
SRES B2
SRES B1
SRES A2
The Day After Tomorrow? Very unlikely!
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Myth 5
Everyone jumps on the negative effects of Climate
Change there’s no need for urgent action.
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Global-average temperature and sea level are
projected to rise under all scenarios
 Global-average surface temperature projected to increase by
1.4 ºC (~2.5 °F) to 5.8 ºC (~10.5 °F) by 2100
Rate of warming likely unprecedented in at least last 10,000 yrs
Land areas will warm more than the global average
Global average precipitation will increase over 21st century
Very likely to be more intense precipitation events
Snow cover and sea-ice extent projected to decrease further
Glaciers and icecaps projected to continue widespread retreat
Global mean sea-level projected to increase by 9 cm (~3.5 in) to
 88 cm (~34.5 in) by 2100
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COASTAL POPULATIONS AT RISK
Change from the present day to the 2080s
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University of
Middlesex
IMPACTS ON THE UK
 Coastal flooding from sea-level rise
 River flooding from more heavy rain events
 Health risks
 Water supply threatened by droughts
 Increased storminess?
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HOW QUICKLY WILL THE CLIMATE CHANGE IN FUTURE
 Depends on…………
 How much greenhouse gas emissions grow
 this depends on population growth, energy use, new
technologies, etc
 How sensitive the climate system is to emissions
 how clouds, ice, oceans etc respond to the extra heating;
we build a mathematical model of the earth’s climate
system to calculate this
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WHAT CAN BE DONE?
Adaptation
coping with the effects of climate change
Mitigation
reducing emissions of greenhouse gases
soaking up CO2 by forests, etc
reducing sensitivities
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Things you can do today at no cost:
•Turn off lights when you leave a room
•Only boil the amount of water you need in your kettle
•Turn off televisions, videos, stereos and computers when they are not in
use - they can use between 10 and 60% of the power they use when on
•Don't leave fridge doors open for longer than necessary, let food cool down
fully before putting in the fridge or freezer, defrost regularly and keep at the
right temperature
•Close curtains at dusk to keep in heat
•Let your clothes dry naturally rather than using a tumble drier
•Turning down the thermostat for your heating by 1 degree could cut your
heating bill by 10%
•Set your water thermostat for 60 degrees - this is plenty warm enough for
bathing and washing and will save money too
•Use economy programmes on dishwashers or washing machines
•Where possible don't stand cookers and fridges/freezers next to each
other
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Things you could do in the future
•Put foil behind radiators fitted on external walls
•Use energy saving lightbulbs - they use a quarter of the electricity and last
much longer
•Insulate your hot water tank and pipes
•Speak to your energy provider about their 'green tariff' - they may be able
to match your energy consumption with an equivalent amount of energy
from renewable sources
•Fit seals to externals doors, skirting boards and floor boards to reduce
heat loss - 15% of heat is lost through draughts and 15% through the floor
•Make your windows draught proof or fit double glazing - this cuts heat loss
in half - up to 10% of heat is lost through uninsulated windows
•Fit loft insulation - which should be at least 200mm thick to be most
effective - 25% of heat is lost through an uninsulated roof
•Fit wall insulation - up to 33% of heat is lost through uninsulated walls
•Replace old inefficient boilers
•Fit solar panels or solar tiles to your roof
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Links: www.metoffice.gov.uk
www.bbc.co.uk/climate
www.royalsoc.ac.uk
www.ipcc.ch
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