IPCC report

The Intergovernmental Panel on Climate Change has released the final installment of its latest report, focusing this time on strategies for dealing with CO2 emissions. The earlier reports, released last September and in March, laid out evidence that human activity is causing global warming and examined the impact this will have on human life. This final installment investigates solutions, with particular focus on curbing industrial greenhouse gas emissions.

DW spoke with Dr. Edgar Hertwith, a professor of industrial ecology at the Norwegian University of Science Technology and a lead author of the IPCC report.

DW: This report seems to be shifting towards solutions. Carbon capture and Sequestration (CCS) is part of the package of ideas on the table. Can you explain what CCS is?

Edgar Hertwith: CCS is a technical process. It's basically a cleaning of the off-gas from power stations and iron mills where you scrub out the CO2. That pure CO2 is pumped through a pipe into a geological reservoir, where it's stored.

So this means gathering CO2 and storing it underground?

The CO2 is from the stream out of a power station - the off-gas that comes from combustion. It already has an elevated concentration of CO2 about 20 percent depending on whether you burn coal or gas.

Critics say there is no scientific consensus on whether or not ‘carbon negative' technologies like this actually work. How do you respond to that?

I think technically they can be made to work, but whether they will work in the larger system, yes, that remains to be seen.

Can you give us some other examples of CCS?

CCS is being used today on a limited scale to clean natural gas. Some natural gas has a high content of CO2. For example, at In Salah in Algeria and at the Sleipner field on the North Sea, this CO2 to is being captured and pumped down into aquifers. These are the applications that exist today. There are also applications in North America where natural CO2 deposits and CO2 from industrial facilities are being injected into oil fields. This has the economic advantage of increasing the amount of oil that can be produced.

How stable is CO2 once it has been pumped underground?

There are different geological formations that have different properties. We can draw the parallel to natural gas: We find natural gas in geological reservoirs where it has been for hundreds of thousands, even millions, of years. But we also know there are other places where natural gas initially formed and where it has escaped. So basically, we need to understand the geology that is able to keep the CO2 for long periods of time.

This report is intended to influence policymaking around the world. What is your goal here?

We want to show the different options that we have to reduce greenhouse gas emissions - and to illustrate the strengths and weaknesses of these different options. We're trying to provide an understanding of how far we've come with the climate policies that have already been implemented. And some feedback on what policies are more or less effective.

Can you give me an example of an effective policy?

The German feed-in tariffs for renewable energy have been very effective in stimulating the development of renewable energy technology - and creating an alternative to fossil fuels.

Can you give me an example of climate policy which is not working?

I don't think the European Emission Trading System (EU ETS) is working at this point. There have been too many permits issued. The basic idea of the EU ETS is to put a price on CO2 emissions. But this price today is close to zero. The result of that is that we use coal-fired power plants instead of gas-fired power plants and the emissions in Europe are actually increasing; whereas, emissions in the United States, which does not have such a policy, are decreasing because there they are producing larger amounts of natural gas and displacing coal.

What is the emissions budget?

The idea is we have a finite amount of CO2 that we can emit into the atmosphere. The atmosphere is basically a fixed volume - think of it like a bucket. If you add CO2, you have reached the concentration of CO2 that will produce temperature rise. So if we want to stay below 2 degrees global average temperature rise above pre-industrial levels, then we have to limit CO2 concentrations to below 450 parts per million.

So, if you divide the amount of CO2 we can produce by ten bilion people you get about a hundred tons. That's the total amount that we can emit. Problem is, we are using up this amount quite quickly. In Germany, for example, the average person emits about 15 tons of CO2 per year. That means you go through this hundred-ton budget in seven years.

Beyond finding technology to help deal with CO2 we are producing now, how does this report encourage changes in the way we live, so we actually produce less CO2?

There is the issue of transportation. We have a lot of freedom to choose our mode of transportation. We can use cars, bicycles, public transportation. Here, consumers have a significant ability to reduce their CO2 emissions.

The other area is in the field of nutrition. People are eating more and more meat because they are becoming wealthier. The problem with meat is that this diet produces far more emissions than a vegetarian diet. The IPCC will actually discuss these different diets and what kind of greenhouse gas implications.