The European Union needs to “significantly improve its policy package” for 2030 in order to align itself with the emission trajectories of the Paris Agreement, according to renowned Belgian climate scientist Jean-Pascal van Ypersele.
Jean-Pascal van Ypersele is Professor of climate and environmental sciences at Université catholique de Louvain. He is former Vice-Chair of the Intergovernmental Panel on Climate Change (IPCC).
He spoke to EURACTIV’s energy and environment editor, Frédéric Simon.
- EU’s updated 2050 low-carbon economy strategy needs to be consistent with Paris goals
- This means “a very significant strengthening” of the EU’s 2030 targets
- Reaching net-zero emissions in just thirty years requires “a turnaround” in policies
- “Big uncertainty” remains over the size of warming associated with a doubling of CO2
- Ice sheets sensitivity to warming is still “somewhat uncertain”, could have “huge consequences in terms of sea level”
- “Jury still out” on whether Sahel region will see more humid or drier climate
- Belgium’s dry summer of 2018 “illustrates weather conditions we may see more and more”
- “There is still a chance” of avoiding to cross the 1.5°C warming line
- Meeting the 2°C or 1.5°C target requires “paradigm shift” in both cases
- “The deadline in a sense is behind us already”
The European Commission is launching a public consultation on 10 July to update its low-carbon economy roadmap for 2050. How should the EU approach this? What are the key objectives that it should aim for?
Consistency and ambition are the two keywords here.
The EU has ratified the Paris Agreement, which has very ambitious objectives in terms of keeping the rise of global temperatures “well below 2°C” as a minimum and “aiming for 1.5°C”.
And that means a very significant strengthening of the EU 2030 target of reducing emissions, which forms part of the so-called nationally determined contribution, or the EU effort under the Paris Agreement.
What the EU deposited in the UN framework was prepared in 2014, before the Paris Agreement. This means that the EU contribution is largely based on policies which are outdated. Hence, the EU needs to significantly improve its policy package so that its ambition level is brought in line with the temperature objectives and the emission trajectories of the Paris Agreement.
It will also help restore the EU climate leadership position that it had in the past but that it is busy losing to China.
As part of the roadmap, the European Commission has been tasked with defining the EU’s remaining carbon budget for 2050. Do we already have an idea of the size of that budget?
The numbers at this stage are not clear. But what is clear is that they have to be much lower than before the Paris Agreement, which raised the ambition in terms of global temperature objectives.
One should also realise that in the past the EU’s carbon budget for staying below 2°C was essentially based on a probability level of only 2 out of 3. This is a low probability, which means implicitly that the EU contribution is not only unambitious and outdated – as I explained – but it also needs to be based on a much higher probability level of success.
No engineer would ever build a bridge with only two chances out of three of getting to the other side when you cross it. So all this means that the EU’s carbon budget needs to be significantly smaller than what it was up to now.
Assuming the EU aims for net-zero carbon emissions, what would be the implications in terms of the scale of socio-economic transformation required?
It’s a huge transformation. Reaching net-zero carbon emissions in just thirty years requires a great effort to renovate the entire building stock in Europe, to completely change the mobility system, to develop renewable energy on a massive scale, to transform the industry so that it is much more efficient and much closer to being really circular, to protect the carbon content in soils and forests in the agriculture and forestry sectors much more effectively, etc.
It’s really a turnaround that would need to be organised and mainstreamed in all European activities and policies.
But you do agree that the net-zero carbon emission goal for 2050 is a sound objective for Europe from a scientific point of view in terms of climate change mitigation?
Certainly from the climate point of view, to have real net-zero European-wide economy would be most welcome and a significant contribution to the global effort, on the condition that the EU policies do not result in emission increases elsewhere.
We also need to realise that by 2050, the EU will represent 5% of the world’s population, with a share of global emissions that will be significantly lower than now. This means that European climate policies are at least as important through their effects elsewhere as they are internally.
Now, that is just carbon dioxide. There are also other greenhouse gases which, unlike CO2, cannot be absorbed in what we call carbon sinks. You can absorb CO2 by managing forests more efficiently but doing that for methane from agriculture for example is much more difficult. There, you need to reduce emissions, for example by reducing meat consumption.
So I would say it’s a huge transformation that would be needed. And the scale of it would require mainstreaming climate policies in all EU activities, not just energy.
You were one of the lead authors of the third report of the IPCC, which was published in 2001. Broadly speaking, how far have we gone since then? What are the big remaining uncertainties, in terms of understanding the causes of climate change, and its impacts on the environment?
One of the largest remaining uncertainties is the real sensitivity of the climate system to an increase in greenhouse gas concentrations. This means that, if we double the amount of CO2 in the atmosphere of a climate model, we still have a factor 3 difference between the lower and upper values for the estimates of temperature rise after the system has entered equilibrium with the new CO2 concentration.
This “climate sensitivity” is somewhere between 1.5°C and 4.5°C. So, it’s a big uncertainty. That is also a call for caution because the sensitivity might be on the high side of that range. If it was on the high side, it would require even bigger efforts than by assuming an average sensitivity, which is what is being done currently.
That factor of 3 has been there basically for the last forty years without much change. To a certain extent, it’s due to the difficulty of modelling the behaviour of clouds in the climate system. And that would require better measurements of the details of cloud behaviour and climate models and super-computers with much higher spatial resolutions than what we’ve been able to afford until now.
That being said, the uncertainty relates to the size of the warming associated with a doubling of CO2 concentrations. It is not an uncertainty on why the climate is warming, that is very clear. Since 1950 approximately the climate has been warming mostly because of greenhouse gases coming from human activities, and not for any other reason. There is more than a 97% consensus in the scientific community about that conclusion.
So that remaining uncertainty doesn’t remove anything from the urgency of reducing emissions to zero or net-zero as quickly as possible, on the contrary.
Now, in terms of impacts, one of the largest uncertainties is the risk of having a high amount of sea-level rise over the coming centuries. This is related to a large extent to the stability of the Greenland and West Antarctic ice sheets in a warming climate. And that would have consequences for hundreds of millions of people across the world over the coming centuries – even if the ice sheets don’t melt quickly, they take centuries to melt, if not millennia.
The other significant uncertainty in terms of the impact of global warming is the changes in the distribution of precipitation, for example in Africa. For Northern Africa it’s clear, on average we’re going to see a drying of climate conditions. But in the Sahel for example, things are much less clear. Are we going to see a more humid or drier climate?
The jury is still out to a large extent about that. And of course it matters a lot for agriculture and food security in that part of the world.
Is there a chance that Belgium could resemble a Mediterranean country in the near future? Maybe some of us in Brussels wouldn’t be too unhappy about it…
The climate in Belgium will become warmer – that is very clear. It is also clear that there will be changes in precipitation patterns.
In addition to the inevitable warming, we’re also going towards drier summers. And I’m not saying that because we are in a dry summer this year, because one year is not the climate. But what we’re seeing now is an illustration of the kind of the weather conditions we may see more and more. This is hardly a reason to be happy, as it will create difficulties for agriculture, water supply, etc.
On the other hand, we’re also going towards wetter conditions in winter. The average over the year won’t probably change so much because the decrease in summer precipitation would probably be compensated by an increase in winter. But on a seasonal level, there would be a significant difference.
Now, that doesn’t translate clearly towards a Mediterranean climate – that would be a caricature. But still, it would mean significantly different weather conditions for Belgium.
Climate mitigation has often focused on reducing CO2 emissions. But what about other global warming gases such as methane? Are they being neglected?
The other gases matter as well, and we should not forget them. But there is some justification for focusing more on CO2.
Methane is thirty times more potent for heat-trapping than CO2 over a hundred-year timeframe, which calls for keeping methane emissions under check. But there is much more CO2 emitted – we’re talking about dozens of billions of tonnes of CO2 per year – while for methane we’re only talking about millions of tonnes per year.
In total, CO2 represents about 80% of the total gases of human origin which are warming the planet. That’s why CO2 is mentioned so much more than other gases.
Still, the remaining 20% is a big deal. So you absolutely need to deal with methane, N2O, CFCs, HFCs, HCFCs, and all their cousins. But if you focus on them and forget the CO2 you would be making an even bigger mistake.
The IPCC is currently working on a report to assess the difference between global warming of 2°C and 1.5°C. From your own understanding, what is the difference between the two in terms of environmental impact?
Obviously, the environmental impact is lower with global warming of 1.5°C than with 2°C. And for various sectors, it can make a big difference in some parts of the world. For example, on the long term sea level rise.
The sensitivity of ice sheets to warming is still somewhat uncertain so the difference could be big. At 1.5°C, one could be at the limit of the conservation temperature for the two ice sheets that I mentioned before – the Greenland ice sheet and the Western Antarctic ice sheet.
At 2°C, you might be above the conservation temperature for at least one of the two. An ice sheet that stays above its “conservation temperature” long enough melts. And that could have huge consequences in terms of sea level. Remember just the Greenland ice sheet is equivalent to 6 to 7 metres of sea-level rise globally.
On the other hand, the report will also assess those options to decrease emissions of CO2 and other gases in order to keep with a 1.5°C warming scenario. And that is significantly more difficult and ambitious than to stay within a budget compatible with 2°C.
So there are very good reasons to shoot for the 1.5°C objective. But it requires a much higher ambition level because we have emitted so much gases already. One should always remember that 15 to 40% of each tonne of CO2 that we emit today will still be in the atmosphere in 1,000 years from now. So the inertia in the carbon cycle is huge.
This basically means there should be a much higher sense of urgency to reduce emissions. Because every year, month, or day that goes by adds another layer to the thermal insulation that we have been installing over the planet. This is why we urgently need to get as quickly as possible to zero emissions.
The global rise in temperatures has already reached 1.1°C. So is it even possible to meet the 1.5°C objective?
It’s a bit too early to comment because the IPCC report is still being finalised.
But I think one of the key messages of that report is likely to be that the climate of the future is not a fatality. It is not written in the stars that we will go above 1.5°C. It very much depends on the ambition level of the countries and actors of the world.
Today, we are indeed at 1.1°C of warming. Because of the inertia of the climate system, we are booked for another few tenths of a degree, but not four tenths. If there was enough political will at the appropriate scale, there is still a chance to avoid crossing that line.
And if we are unable to avoid crossing that line, we could at least minimise the time of overshooting that 1.5°C threshold. It would matter a lot to go back below that limit as quickly as possible. The longer we would stay above that line, the higher the risk of ice sheet instability and sea-level rise.
So one should not think at this stage that it is too late to stay below 1.5°C.
But what kind of timeframe is left to reach the 1.5°C objective? How fast is that window of opportunity closing?
There is no strict window. There is a very high level of urgency but I’m always hesitant to use the kind of deadlines that some of my colleagues have used in the past saying we have three or ten years left.
Things are not black and white. We’re trying to manage risk. And the longer we wait to reach the peak of global emissions and reduce global net emissions to zero, the more warming will occur. And the longer we will stay above 1.5°C.
I find this concept of window of opportunity a bit dangerous. Because if the window closes, it becomes very demotivating for everybody to continue to act. We give the impression that the battle is lost. And that can only worsen things. The urgency to act is clearly there.
The deadline in a sense is behind us already. Ideally, we should have acted much earlier. We are in a kind of recovery mode now, running behind a train which has already left and which is going faster and faster. That’s how I see things.
You said meeting a 1.5°C target would be much more difficult than a 2°C target. What are the main differences between the two scenarios in terms of mitigation pathways?
In both cases, what is need is a paradigm shift in the way we use energy and resources in the world. In both cases, it requires a systemic approach. We need to question the way we have used energy until now as if it didn’t matter how much or what kind of energy we use. So in any case, transformational change is needed.
The only difference is that for meeting the 1.5°C target, as the IPCC wrote in its 5th report already in 2013-2014, the speed of transformation needed is much higher. By the way, we should remember that the Paris Agreement doesn’t juxtapose those two targets. It speaks about “well below 2°C” not 2°C or below 2°C, as the Copenhagen Accord or the Cancun Agreement did.
For me, “well below 2°C” doesn’t mean 1.9°C, it probably means 1.75°C, which is in the middle. But in all cases, it’s transformational changes that are needed, a paradigm shift. And the closer you want to get to 1.5°C the faster those changes will have to happen.
… and keeping fossil fuels in the ground in any case.
As quickly as possible, yes. And we can all help if we want. I’ve done it in my house, I don’t use any fossil fuels anymore. I’ve been culprit of using heating oil for two decades and it’s now over. Everything in my home is now powered by renewable energy, including my heating system, my small car, which is fully electric.
So it is possible to decarbonise, it’s only a matter of accelerating the transition so that as many people as possible can do it – not just climate scientists or university professors. And for that, those dealing with government budgets, but also financial institutions and the banking sector have a big responsibility to facilitate that transition.