Transcript Climate change

GREEN FUTURES
Session 1
Climate Change
Dr. Steven Robert Harris
Science Shops Wales
University of Glamorgan
Main Messages
 The scientific evidence tells us that climate
change due to global warming is very real and
very urgent
 Climate Change will affect us here in Wales,
both directly and indirectly  We need to act now…
 … and we can all do something to help!
 But… we also need to understand that global
warming is just one aspect of a wider Earth
system crisis caused by human activity……
The Earth is one great living system….
…of interacting physical, chemical and biological
processes…
…and four great cycles that sustain life….
The Hydrologic Cycle – fresh water to drink
The Nitrogen Cycle – food for all to eat
The Oxygen Cycle – for all to breathe
The Carbon Cycle – fuel for all to grow
The Anthropocene – the age of human impacts…
“Over the last two decades a new imperative has come to dominate
environmental concerns. With a rapidly increasing understanding of the nature
of Earth’s life support system, a growing awareness has emerged that human
activities are exerting an ever-accelerating influence on aspects of Earth
System functioning upon which the welfare and the future of human societies
depend.”
IGBP Global Change and the Earth System: A Planet Under Pressure (2004)
Increasing rates of change in human activity since the
beginning of the Industrial Revolution (1)
International Geosphere-Biosphere Programme (2004). Global Change and the Earth System: A Planet Under Pressure
A Prosperous Way Down?
Exploring Gren Economic Futures
for Wales
Increasing rates of change in human activity since the
beginning of the Industrial Revolution (2)
International Geosphere-Biosphere Programme (2004). Global Change and the Earth System: A Planet Under Pressure
Global-scale changes in the Earth System as a result of
increases in human activity (1)
International Geosphere-Biosphere Programme (2004). Global Change and the Earth System: A Planet Under Pressure
Global-scale changes in the Earth System as a result of
increases in human activity (2)
International Geosphere-Biosphere Programme (2004). Global Change and the Earth System: A Planet Under Pressure
A Prosperous Way Down?
Exploring Green Economic
Futures for Wales
Earth’s atmosphere – protecting and sustaining all
Composition of Earth’s atmosphere
Gas
Nitrogen (N2)
Oxygen (O2)
Water Vapour (H2O)
Carbon Dioxide (CO2)
Methane (CH4)
%
78
21
Variable (0-2%)
0.038 (388.63 ppm)
0.0018 (1.8 ppm)
Some definitions
 Weather: the short-term (hourly, daily) state of the
atmosphere, determined by variables such as
temperature, wind, moisture, and pressure.
 Climate: The long-term (years, decades – typically 30
years plus) average weather of a region: typical weather
patterns, the frequency and intensity of storms, cold
spells, and heat waves.
 Global warming refers to the increase in the average
temperature of the Earth’s atmosphere.
 Climate change - the changes in climate that
accompany the warming of the atmosphere, such as
changes in the frequency and intensity of extreme
weather, sea level rise.
The “Greenhouse Effect”…
CO2 concentration in the Earth’s atmosphere increased from preindustrial levels (around 280 parts per million in 1800) to 318 ppm by
1960 and now (2010) stands at 388.6 ppm
Northern Hemisphere temperature record – last 1000 years
Temperature changes so far
Yes, we’re as sure as it gets…
 Intergovernmental Panel on Climate Change –
(IPCC) AR4 Synthesis Report November 2007:
 Warming of the climate system is unequivocal,
and most of the observed increase in globally
averaged temperatures since the mid-20th century is
very likely (>90%) due to the observed increase in
anthropogenic (produced by human activities)
greenhouse gas concentrations.”
 Fully endorsed by:
 The National Academies of Science of all G8 countries and Brazil, India &
China
 The British Association for Advancement of Science
 The American Association for the Advancement of Science
Impacts of climate change - global
•Rising temperatures
•Rising sea levels
•Deforestation
•Increase in extreme
weather events
•Impacts on plants and
animals
•Problems with fresh water
•Problems with food crops
•Spread of disease and
other health problems
•Deforestation
Impacts of climate change - Wales
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Average temperature increase 1.5 - 4.5 C
Hot summers (similar to 1995) up to 2 years in 3
Dry summers (similar to 1995) up to 1 year in 2
Milder winters
Reduction of snowfall - down by 50 - 90 per cent
Increase in winter rainfall by up to 20 per cent
Frequency of winter intense rainfall events - doubling from 1.5 to 3
events per winter
 Decrease annual soil moisture content by 0 - 20 per cent
 Increase in average length of thermal growing season by 40 - 100
days
 Sea level rise 23 - 36 cm. (Including vertical land movement the net
sea level rise likely to be 11 - 71 cm
– UKCIP Climate Change Scenarios 2002
Winter
Summer
So, what’s to be done?
 Be honest about what’s needed - 6-9% reduction in GHG
emissions every year!
 Acknowledge the equity implications – CC will affect
some much more than others…
 Recognise individual and collective responsibility
 Be innovative and courageous in developing policy
 Immediate end to burning of coal
 Drastic reductions in use of oil and gas
 World-wide Carbon Tax
 Rapid take up of ‘cleantech’ by industry and transport
 Decarbonisation of agriculture and food supply chains
 Rapid and massive increase in renewable energy
generation
 Nuclear? Creation and burial of charcoal (biochar)?
Geoengineering?
Do Nothing?
"We cannot go on this way for long. We cannot continue
with business as usual. The time has come for decisive
action on a global scale. …this challenge, and what we
do about it, will define us, our era and, ultimately, our
global legacy.
We all need to shoulder this responsibility, not just for
ourselves, but for our children and their children.
Will succeeding generations have to ask why we failed to
do the right thing, and left them to suffer the
consequences?“
 From the address by UN Secretary-General Ban Ki-moon to the
General Assembly thematic debate on climate change, New York,
31 July 2007
GREEN FUTURES
Session 1: Climate Change
Thank You
Dr. Steven Robert Harris
Science Shops Wales
University of Glamorgan
Fossil fuel burning and atmospheric CO2
Since 1700, 600 Gt (gigatonnes = billion
tonnes) of carbon as CO2, have been
released by fossil fuel burning.
This has increased atmospheric CO2 from
280 ppm to over 380 ppm.
About 45% of CO2 we have emitted has
stayed in the atmosphere – the remainder
has been taken up by the oceans and land
vegetation
Carbon “sinks”
At present, the soil and land plants are
acting as carbon “sinks” – taking up CO2
from the atmosphere and slowing down
the rate of increase.
It seems they only have a limited
capacity to do this – we may now be
approaching this limit
• Evidence from Sea of Japan…
Climate change – what is “dangerous”?
 Given that global climate change is already
underway and that as a result of more fossil
fuel emissions, more change is inevitable,
many scientists and politicians have asked:
“How much warming would be
dangerous?”
 This is a difficult question to answer, not least
because we would need to specify “how much
danger” and “to whom”.
 However, for various reasons, many scientists
have assumed that any rise of more than 2oC
above “pre-industrial” (about 1900)
temperatures would be highly dangerous.
Why 2oC?
 It is expected that a rise of more than 2oC would bring a
very high risk of a range of disastrous effects, such as:
 Unstoppable melting of the Greenland ice sheet. The
complete melting of the ice sheet would raise sea level by
6-7m;
 Drastic changes to global weather patterns causing
widespread changes to natural environments (e.g. spread of
deserts, loss of tropical forests) and major falls in food
production due to droughts;
 Many positive feedbacks coming into play to rapidly
increase temperature much further. Some experts have
said that instead of a range of temperature changes, we
have just two choices: a rise of not more than 2oC, or a
rise of at least 6oC which would effectively terminate our
techno-industrial civilisation in its present form.
The Current Situation
 On a per capita basis, the nation responsible for putting the largest amount
of carbon dioxide in the atmosphere is Britain - because the Industrial
Revolution started here.
 China is now the largest annual emitter of carbon dioxide
 It now seems almost certain that global temperatures
will rise by 2C to 4C over the century
 Rising temperatures will melt ice and cause ocean water to heat up and
increase in volume. Estimates of sea-level rise vary from between 18 and
59 centimetres to one to two metres.
 1-2 metres sea level rise would make the Nile Delta and Bangladesh
completely uninhabitable, along with much of south-east England, Holland
and the east coast of the US
How much, how soon?
 The adjustment of GHG concentrations in the
atmosphere to reductions in emissions depends on the
chemical and physical processes that remove each gas
from the atmosphere.
 Concentrations of some greenhouse gases decrease
almost immediately in response to emission reduction,
while others can actually continue to increase for
centuries even with reduced emissions.
 The rate of emission of CO2 currently greatly exceeds its
rate of removal
 small to moderate reductions in its emissions will not
result in stabilisation of CO2 concentrations, but will only
reduce the rate of its growth in coming decades.
How soon? Now.
 “To have any chance of avoiding dangerous
climate change we need to get our CO2
emissions under control within the next few (515) years. Changing the supply-side simply can’t
do enough quickly enough – so large-scale
clean generation projects won’t help much in the
short term unless…we rapidly and dramatically
reduce our energy demands” – The Tyndall
Centre
 “To avoid the most catastrophic effects of
climate change, world carbon emissions will
have to drop to near zero by 2050 and "go
negative" after that” - the Worldwatch Institute