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Why – and how – Man must take responsibility for climate change

Dr Martin Todd, Sussex's new Chair in Climate Change

The Copenhagen summit on climate change is in its final and most critical week, amid claims of scientific conspiracy and threatened international divisions and protest violence.

Here, University of Sussex Professor in Climate Change Martin Todd offers his own perspective on the issues at stake, and discusses why it is important for the 192 countries attending to cooperate on one of the biggest challenges facing our planet.

Why the fuss about climate change and global warming? Aren't they natural phenomena, over which we have little or no control?

There are indeed many natural causes of changes in the earth's climate and in the more distant past (more than say 10,000 years ago) the Earth has experienced a wide range of climates, both colder and warmer than today. Crucially, however, the rapid warming we have experienced since the mid-20th century has been largely caused by human activities, mostly burning fossil fuels and other industrial activities. This activity has altered the energy balance of the planet and caused most of the recent warming of about 0.7C.

While science can never be 100 per cent certain, this view is accepted as being beyond any reasonable doubt by the vast majority of climate scientists and policy makers. Recent accusations of a scientific “conspiracy” to hide data that undermines this view are simply a smokescreen created by an increasingly isolated group of climate change deniers. There is no scientific fraud: the evidence of global warming comes from a variety of independent sources.

Finally, since we have caused these changes to climate, we do in principle have the means to rectify the problem.

What are the short-term and long-term predictions for the impact of climate change on the planet?

The longer term projections (longer than say a decade or so) are for a warmer world, substantial changes to rainfall patterns, more extremes in weather, melting of snow, glaciers and sea ice and rising sea levels.

The crucial question is the magnitude of these changes. This depends substantially on the level of greenhouse gas emissions in the next few decades. If we continue along our current emissions trajectory we can expect the world to be about 4C warmer, globally, than today, before the end of the century. Temperatures increases over land regions would be even greater, especially in the polar regions. It is truly hard to imagine what kind of world that would create. The climate conditions suitable for agricultural regions would either shift thousands of kilometres or disappear altogether in many regions, including much of Africa and India.

The Greenland ice sheet would start to break up, leading to sea level rise of many meters. Most of the world's existing delta regions and indeed major cities would be under threat. Add to that the acidification of the oceans, stresses on water resources and we face an unprecedented global planning challenge.

Even if we implement all the emission reduction targets suggested by the major polluting nations at the start of the Copenhagen summit, it is not really likely we can limit global temperature rises to 2C. This requires more stringent targets.

One further aspect that people should be aware of is that because carbon dioxide accumulates in the atmosphere, the longer we wait to reduce emissions then the greater and more difficult the cuts will have to be. That is why the need to act now on climate is actually a science-based imperative .

Which human activity has the most negative impact on climate change?

In terms of emissions, the biggest single sector is energy generation. In our present system economic growth has been fuelled by burning fossil fuels. The world economy is built on this source of energy. In the end, most of our consumption contributes to greenhouse gas emissions. 

Can research into climate change make a difference (short-term to long-term) to predicted outcomes?

Climate research is absolutely crucial. Although the issue is now highly politicised, it fundamentally rests on the findings of climate scientists. Right now we need to know the magnitude of future climate change, globally, regionally and locally in order to determine (i) what magnitude of emission cuts are necessary; (ii) what kinds of policies are likely to achieve stabilisation of carbon levels in the atmosphere; (iii) what kind of impacts we will have to deal with i.e. water availability, crop yields, coastal protection. There are many gaps in our understanding that need to be addressed to improve the projections of future climate.

Are their any net benefits to climate change?

Globally, it would be very hard to make the case that having to adjust to substantial changes in our life support systems can be beneficial. For most people in the world life is hard enough already.

Is geo-engineering (using new technology to capture and dispose of CO2 emissions) our only hope of counteracting the effects of climate change?

No. Substantial and immediate cuts in greenhouse gas emissions and deforestation is the best first step. At the same time we need to build resilience to climate, for example by using land and water resources more efficiently.

What is the greatest challenge to a global climate change policy?

As always, we are constrained by our history. The modern world is structured around competing nation states (or blocs of states) and large multi-national commercial conglomerates, and to the first order operates to ensure economic growth and profit.

Therefore the global political system is not well designed to deal with an issue such as climate change which (i) affects the entire planet; (ii) places physical limits on use of key natural resources; (iii) requires long-term international coordination and planning and; (iv) will cost a lot in the short term.

How will your research make a difference?

The University of Sussex recently launched a climate initiative which seeks to build multidisciplinary research into climate change. The negotiations at Copenhagen clearly demonstrate the complex web that climate change now represents; involving science, economics, geo-politics, ideology, public opinion, culture and technology. The initiative at Sussex involves many groups on campus, notably the Department of Geography, the Science and Technology Policy Research Unit (SPRU) and the Institute for Development Studies (IDS). Our research agenda spans climate science, climate policies related to both mitigation and adaptation, and the implications of climate change for poverty in the developing world.

We have launched two new and unique Masters courses in Climate Change and Policy and Climate Change and Development through which we hope to help develop decision makers who can find appropriate solutions to the immense challenges we face.

Is the younger generation really clued up about what's happening to the planet?

Opinion polls suggest older people are likely to be more sceptical than the young. However, I think that climate change is really frightening for most people. I can understand how this can lead to apparent apathy. If something is too challenging we can often simply put our heads in the sand. My feeling is that the kind of substantial cuts in greenhouse gases that are necessary will hurt the material standards of living for most people in the West in many ways. No one wants to face up to that. Unfortunately, we have no choice. If we don't engage with the issue then those who run society may propose solutions in which the weaker sections of society pay the biggest price. Look who's paying for bailing out the financial system. If there is a good side to climate change, then perhaps its the wake up call we needed.

Notes for Editors


Professor Martin Todd is a climate scientist whose research interests include the role of mineral dust aerosols in the climate system; climate change impacts on hydrological systems; and variability in the tropical climate system.

For further information on Climate Change study and research programmes at the University of Sussex, see: Climate Change

University of Sussex Press office contact details: Tel: 01273 678 888 or email


Last updated: Wednesday, 16 December 2009