Shell World Online

Mustering the energy to tackle climate change

November 16, 2007

Q:   Is this year’s extreme rainfall in many parts of the world a sign that climate change has begun?

A:   Yes, climate change is happening. Our latest report confirms that. Temperatures have gone up, rainfall on average has increased. There is a simple explanation. When the atmosphere gets warmer there is more moisture and more “moisture turnover”, with more cloud formation and rainfall as a result. This does not mean that there is more rainfall everywhere. Weather patterns are changing, and in some places it is getting dryer instead of wetter. But there’s no doubt that climate change has begun.

Q:   The Intergovernmental Panel on Climate Change (IPCC) published its fourth Assessment Report this year. What is its most important message?

A:   As far as the report on mitigation is concerned, the message is two-fold. We have become more optimistic that mankind possesses the technologies to greatly reduce emissions of greenhouse gases and limit climate change, but we have become more pessimistic about the time left to do that. Once CO2 and other greenhouse gases are in the atmosphere they don’t disappear quickly. There’s an accumulation of gases. At this moment our emissions are continually increasing, so the amount in the atmosphere is increasing as well. To stabilise the concentration of greenhouse gases in the atmosphere, we have to reduce our emissions very steeply. The lower we want to keep the level of greenhouse gases, the earlier this steep reduction has to happen.

Q:   At which level should the concentration of greenhouse gases in the atmosphere stabilise?

A:   Of course it depends on what level of climate change you think is acceptable. That’s a political decision. The latest scientific insights are that a doubling of greenhouse gas levels compared to levels before the industrial revolution would lead to a temperature rise of approximately 3 degrees Celsius (5.4 degrees Fahrenheit). That is more than we had assumed in earlier reports. At that level of warming many negative impacts can be expected, such as droughts, flooding, loss of ecosystems, coastal erosion and flooding, declining productivity of food crops, and the effects on health.

The European Union has repeatedly stated that the global temperature should not rise by more than 2˚C (3.6˚F), given the risks of climate change. Today, the temperature is already 0.7˚C (1.3˚F) above pre-industrial revolution times. So the 2˚C is a very stringent goal, and while some countries and non-governmental organisations support that goal, other countries don’t support it because they think it is not feasible. But if we take the European goal as the yardstick, we should stabilise the concentration of greenhouse gases at a level of 450 parts per million (ppm), measured as CO2 equivalent. Today, we are at 375 ppm CO2 equivalent. We have only around 10 years — and certainly no more than 20 years — to stop the increase of emissions, after which they should begin to decline sharply. It will require a lot of decisive policy action and timely investment.

Q:   What is the difference between CO2 and CO2 equivalent? And is it relevant?

A:   CO2 equivalent refers to all the greenhouse gases weighted by their global warming potential. CO2 currently makes up around two-thirds of all greenhouse gases in the atmosphere. One-third is made up of methane, nitrous oxides and fluorinated gases. Then there are aerosols — these are fine particles, for example from sulphur and nitrate emissions.

And, yes, the difference between CO2 and CO2 equivalent does matter. To understand climate change as a whole and what you can do about it, you also have to look at the other gases. One of the reasons the IPCC has become more optimistic about the world’s ability to prevent climate change is that if you fully exploit the possibilities to reduce emissions of non-CO2 greenhouse gases, you can cut the overall cost of solutions significantly. Technical fixes are easier and less expensive for some of the other gases than for CO2, which is so deeply intertwined with our energy system and our way of life. For example, it is relatively simple to substantially cut emissions of methane and nitrous oxides from industry and waste management.

Q:   Do all greenhouse gases contribute to global warming?

A:   No. While most greenhouse gases cause the temperature to rise, aerosols or fine particles actually have a cooling effect, because they reflect the sun’s radiation. This is what we refer to as the “masking effect” of aerosols. Without these fine particles, we would already be at 430 ppm CO2 equivalent.

Q:   A cynic might say that we can prevent climate change by releasing more fine particles into the atmosphere.

A:   If you don’t mind more air pollution, that’s the way to do it. But most people don’t want more air pollution because it causes all sorts of nasty problems, such as disease and acid rain. Fine particulate matter causes respiratory diseases and leads to premature deaths. That is why we expect aerosol emissions to be reduced substantially in the longer term. As a result their “masking effect” will gradually disappear.

Q:   Are fine particles also responsible for the so-called Asian Brown Cloud?

A:  The Asian Brown Cloud is air pollution, containing a mixture of air pollutants, mostly fine particles. It’s the manifestation of regional air pollution in the whole of South East Asia, indicating that the problem of air pollution is really big. If you go to any of the Asian cities, you can see it with your own eyes.

Q:   Does the Asian Brown Cloud also cause extra rainfall?

A:   Particles play a role in cloud formation and therefore in rainfall. There are indications the Asian Brown Cloud does contribute to changes in regional rainfall patterns, as does climate change. But it is not clear how these changes will work out exactly. We are quite confident about global predictions of climate change, but when it comes to smaller regions, in many regions one model can say it is becoming wetter while the other says that it is becoming drier. We need to improve our understanding of these regional phenomena.

The Asian Brown Cloud and more generally air pollution often have the same origin as CO2, namely the burning of fossil fuels in power plants and automobiles. So reducing CO2 emissions by moving to cleaner energy sources can also reduce air pollution. That’s why it is wise to address air pollution and climate change simultaneously.

Q:   Which are the most important mitigation measures?

A:   You can’t say that any measure is more important than the other; there is no silver bullet, or overarching solution. A rational policy is to work with a portfolio of measures, ranging from greater efficiency in energy production and use, to more wind and solar power and more combined heat and power; from better insulation of houses to greater use of geothermal heat; from cleaner diesel vehicles to advanced electric and hybrid vehicles; and from protecting and rehabilitating peat lands to improved nitrogen fertilizer application techniques. Of course it makes sense to do the cheaper measures first. Energy efficiency improvement scores high on that account, because the investment is usually earned back very quickly.

Q:   What about the capture and storage of CO2 from man-made sources such as power plants, known as CCS?

A:   CCS could play a big role in the effort to reduce global emissions. Without CCS the transition to a low-carbon society will become much harder. CCS is not cheap. It is much more expensive than improving energy efficiency. But it is affordable in comparison with the investments we would have to make without CCS. Without CCS we would have to make drastic reductions in our use of fossil energy, especially coal. So it is quite realistic to expect a big role for CCS in the oil and gas industry, in power generation, in the cement industry and in steel plants, probably beyond 2015 to 2020.

Q:   Which role do you see for the oil and gas industry?

A:   The oil and gas industry should continue to work on energy efficiency. It should also work to further enhance the share of natural gas in the fossil fuels mix. And as the industry moves increasingly into heavy crudes, CO2 emissions per barrel of oil will increase. That’s an issue. CCS is a possible solution for that, although coal-to-liquid processes — even with CCS — would not be better than current fuels. Advancing clean coal technology is important provided “clean” means using coal in combination with CCS.

I also hope that the oil and gas industry will continue to drive hydrogen technology forward. While we probably won’t see it applied before 2030, hydrogen in combination with fuel cells is an interesting option for the transport sector. And last but not least, the industry should continue to work for more biomass-based energy. In combination with CCS, biomass in power generation leads to zero or even negative emissions! Going relatively slow on biofuels is important, because some first-generation biofuels are not very effective from a CO2 perspective. And first-generation biofuels could create competition with food crops and biodiversity protection. Second-generation biofuels have a much better future because we can use non-food crops and plant residues.

Q:   Do you expect countries like Australia, China, India and the USA that don’t support the Kyoto Protocol on climate change to support a new treaty?

A:   Let’s first set the record straight on Kyoto. Kyoto was the first protocol belonging to the United Nations Framework Convention on Climate Change (UNFCC), which was agreed in 1992 and entered into force in 1994. It was universally subscribed to, including by the United States and developing countries. Then there was a unanimous decision in 1995 to develop a protocol that would strengthen emissions reductions.

And it was a very deliberate decision, supported by the United States, not to ask developing countries to take part in actual emission reductions. The reason is that these countries, including China and India, have much lower incomes per person than the developed countries. Developing countries are getting involved in the global action though. The Kyoto protocol created the Clean Development Mechanism. It allows industrialised countries to reduce emissions by investing in projects in developing countries. This has led to many emissions reduction projects and has generated a lot of positive interest in developing countries.

Momentum is building for a new agreement. And this is timely, because the Kyoto agreement will expire at the end of 2012. If the US were to refuse to join a new agreement, you could question how useful it will be. However, public opinion in the US is changing in many states towards greater support for climate change mitigation. And many big corporations acknowledge it is an important issue. Even assuming the US will come on board, the next issue is that, this time, emerging economies like China and India should gradually take on emissions reduction obligations. That’s another big issue that will not be easy to solve.

Hopefully, an agreement to begin negotiations will be reached at the summit of all the parties to the UNFCC in December, 2007 in Bali. The best possible outcome would be if we had a new agreement by the end of 2009.

Q:   Al Gore has reached millions of people with his movie “An Inconvenient Truth”. Is it a helpful contribution to increase public awareness or is he a scaremonger, as his critics say?

A:   Al Gore was very effective in raising awareness. His movie uses the basic facts that you will also find in IPCC reports. There’s some exaggeration here and there, but all in all it is a fairly balanced picture. He, of course, did something that scientists cannot do: he added his personal feelings and emotions. But I think that is one of the reasons people paid attention to what he said. In that sense, he has been very effective in raising awareness, which is absolutely essential for action against climate change.

Q:   If you had a billion euros to spend, would you spend it on measures to reduce emissions or would you reinforce sea- and river-protection infrastructure? In other words: “prevention” or “adaptation”?

A:   It is not a question of “either-or”. Cutting emissions is the most effective way to deal with climate change, because it reduces the biggest problems that would be very hard and extremely costly to adapt to.

For example: if the global temperature rises by 2˚C to 4˚C (3.6 to 7.2˚F), which is within the range of what may be expected if we don’t act decisively, big chunks of ice on Greenland could start to melt. If that were to happen, the sea level could rise by around seven metres (23 feet); it would not happen overnight — it would take a long time. But you would have to be a very confident engineer to think that you can manage that increase by reinforcing dunes and dykes. So it’s not a matter of “either-or”, but a matter of “and-and”.

Given that the time we have left is fairly limited, a massive effort on emissions reduction is warranted. On the other hand, even the most ambitious climate change policy cannot prevent more climate change and adaptation to that reality is crucial, particularly in poor countries that are very vulnerable. It will not be easy. But that should not keep us from trying. 

* Bert Metz spoke to Norbert Both

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