Session 1

Climate Change

Dr. Steven Robert HarrisScience Shops Wales

University of Glamorgan

GREEN FUTURES

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)

A Prosperous Way Down? Exploring Gren Economic Futures for Wales

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

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

A Prosperous Way Down? Exploring Green Economic Futures for Wales

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

Earth’s atmosphere – protecting and sustaining all

Composition of Earth’s atmosphere

Gas %

Nitrogen (N2) 78

Oxygen (O2) 21

Water Vapour (H2O) Variable (0-2%)

Carbon Dioxide (CO2) 0.038 (388.63 ppm)

Methane (CH4) 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 pre-industrial 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

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 responsibilityBe innovative and courageous in developing policy Immediate end to burning of coalDrastic reductions in use of oil and gasWorld-wide Carbon TaxRapid take up of ‘cleantech’ by industry and transportDecarbonisation of agriculture and food supply chainsRapid and massive increase in renewable energy generationNuclear? 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

Session 1: Climate Change

Thank You

Dr. Steven Robert HarrisScience Shops Wales

University of Glamorgan

GREEN FUTURES

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 (5-15) 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