Thank you very much.
It's an honour for me to be here tonight to speak in this very nice series on climate change.
I will talk about giant steps which are needed, very much from a science perspective,
what do we know, what do we know about the impacts of climate change
and how can we actually solve the problems.
I will give a little bit of my own background as a researcher.
I will take one of our integrated projects, the ATEAM project on vulnerability,
on how we actually do the different impacts research.
And then flow through the IPCC,
the urgency of starting to reduce the emissions worldwide soon
and then really trying to answer the question:
can we still limit climate change to two degrees.
And of course I don't want to be an alarmist.
I want to give a message: yes, we can do it.
But it actually needs an awful lot of policy action.
But a lot of sceptics often say the climate scientists are alarmist
and they make things worse or they present it in a very bad way.
In my lecture I will talk to some of these things.
And one of the statements was here by John Houghton,
a former Chairman of one of the working group of IPCC,
who stated: Unless we announce disasters no-one will listen.
And he actually didn't do that.
That was completely made up that sentence by some of the sceptics,
to very much discredit as part of the climate science.
And it's very well written in history of where this statement comes from.
A lot of people say it's from John Houghton's book.
If you take the PDF and search you can't find it.
So there is really a problem there.
And a lot of the sceptical science and how the sceptics as a political organisation deal with it
is actually written in this book and very nicely documented.
It's a little bit U.S. based, but it also has the same things but in Europe.
Emergence of DABS, it starts with smoking, takes acid rain, takes climate change
and that whole political discussion of how to misuse the science is actually quite well described.
I won't go into much of the details in my lecture on that debate.
It's well documented. I very much want to look at the impacts.
And what I do is leading groups of scientists who actually do integrated research.
They are not only ecologists, they are ecologists, economists, chemists.
We bring them together, develop a common language, most of the time in the form of a model,
because then you can very clearly distinguish the different assumptions,
and you don't have to use all the different jargons of economics or ecology etc.,
that people use the same words but mean something completely different.
We publish very much in scientific journals, that actually creates your scientific credibility.
But we also build bridges to society by contributing to the different science policy assessments,
like IPCC or the Millennium assessments, which is this volume here,
very much focusing on the threats to biodiversity and ecosystem services,
the different geo reports of the United Nations Environment Programme.
There is where you bring the science together and you synthesise it for policy making.
And that's very much what my research group does.
And I think one of the publications I am most proud of is actually this cartoon
which was published after one of my publications in the Washington Post.
The evolution has evolved into humans, we use tools and we scoop away one third of the world.
Definitely not sustainable.
And I think this cartoon has had a bigger impact than all my other scientific papers.
But it's that side of communicating.
But communicating is extremely difficult. Scientists often give very clear messages.
But the public or the policy makers don't want to hear them,
or want to hide them in fuzzy words, etc. etc. as very nicely depicted by this cartoon.
And what we do is bring the science together,
bring the different disciplines, trying to develop a whole series of common tools.
And that we did in the ATEAM project.
And the ATEAM project, the acronym stands for Advanced Terrestrial Ecosystem Analysis and Modelling.
It took quite a while to actually come up with the ATEAM acronym.
But the ATEAM looked very strongly at mapping different vulnerabilities in Europe for different sectors,
for different regions, for different systems.
And our ATEAM was actually a group of researchers from most countries in Europe.
And the project resulted in about 20 different PhD theses and a whole set of scientific publications.
Now if we look at ATEAM: very central in ATEAM was actually the concept of ecosystem services.
How do we use land?
How are we depending on the different goods and services provided by ecosystems?
And how can we actually link them? We looked at vulnerability in ATEAM.
And vulnerability as defined also by IPCC is a function of exposure,
if you are not exposed you are not vulnerable.
It's a function of your sensitivity. If you are not sensitive you are not vulnerable.
And your adaptive capacity.
If you are exposed, if you are sensitive, but you can adapt, you are not vulnerable.
For example Switzerland is very vulnerable for sea level rise.
Because they are sensitive all the infrastructure is in the lowest part,
they don't have the knowledge like the Dutch to adapt,
but fortunately it probably won't be exposed. So they are not vulnerable.
The Netherlands is not vulnerable either, because we have the knowledge, we can adapt.
Yes, we are sensitive, yes, we are exposed.
But Bangladesh is very very vulnerable.
And of course if you look at sea level rise the positive message
which I had to give is very much that the trip to the coast will be shorter.
So if you look at impacts, a lot of the studies have actually been looking at potential impacts,
only looking at exposure and sensitivity.
And vulnerability if you really want to take all the three different elements.
And that's what we did in ATEAM.
But we didn't look only at climate change, we look at land use change,
we look at other environmental problems like nitrogen deposition,
the increase in CO2 concentrations which has direct effect on plant growth.
We looked at land use change which again changes the adaptive capacity of different regions.
And we put that in a system to get the maps of vulnerability.
But your adaptive capacity, there's very little literature.
And it's very difficult to measure it or to assess it.
So there we actually involved stakeholders from the different sectors,
foresters, tourism managers, farmers, to actually involve them,
talk to them, show them the results of the different models,
and actually get on that basis the adaptive capacity.
The stakeholder dialogue was extremely important.
But that's also extremely tricky sometimes.
For example, we had the forester who was the Chairman of the European Forest Owners Society.
But the person was Portuguese and he was very much interested in cork oak.
So we developed a model for cork oak because of his own need.
But cork oak is a very very small sector.
And if you look at the wine bottles at the moment,
they are all screw caps on them, or artificial corks.
So it's not a very good part.
So with stakeholders you actually have to look at their hobbyhorses
and really distil the broader picture there as well.
So we looked at private sector stakeholders,
we looked at non-governmental organisations,
but also policy makers in ATEAM.
And I don't want to discuss all the details of the analysis we did in ATEAM
but it was very much scenario based, model based.
And all the different models, for hydrology, for ecosystems, for biodiversity,
for carbon sequestration were using the same scenarios.
So it was the first study where all the input and the output was actually comparable.
And if we look at agriculture, and it was a European wide study,
you actually see that in agriculture the land use change is extremely important.
Population in Europe is quite constant over the coming 50 years.
And productivity increases per hectare, so you actually get a decline in arable land.
At the same time you probably get an increase in demand for bio energy.
That's one of the mitigations for CO2.
But you also get the impact of climate change, and especially in the Mediterranean.
So that shifts some of the agricultural patterns.
And the interesting thing was, when you looked at adaptation
we actually initially thought that countries like France and the Netherlands
would be much much more adaptable than for example the Mediterranean.
But the Mediterranean had a very heterogeneous agricultural system.
And they are actually more adaptable if you look at the data.
Because sometimes the grains produce better, otherwise it's again the olive trees etc.
Because of the heterogeneity some of the sectors really part.
While in the Netherlands it's focusing on wheat.
And if you have a very hot dry summer all your harvest is gone.
So it's that diversification which actually within the agricultural system really sets the adaptive capacity.
But in agriculture you also get the shifts, the Mediterranean is getting drier,
Scandinavia is getting warmer, so you get shifts in crop, very strong regional patterns.
But in agriculture you also see that the soil carbon,
so the carbon uptake, the carbon sequestration in soil changes,
and it's getting warmer less carbon will be sequestered.
But also of course also heavily influenced by the cropping system and the management in there.
For forestry because of the land use change
we will see over the coming 50 years much more forests in Europe.
These forests are relatively young, so they suck up carbon and actually store more carbon.
So it's a positive part.
But again you see the drought in the Mediterranean with some of the impact on forest.
And a very very clear signal which came out of this study was the increase in forest fires,
partly because of the change in land use,
and a lot of bush encroachment and a lot of young forests which are actually sensitive to forest fires,
combined with the drought.
And this was actually one of the issues that was picked up very strongly by some of the stakeholders from the Mediterranean.
And they really said, we don't have to adapt to climate change,
we have to adapt to much more intense fire regimes
and actually change our land use to cope with those kind of things.
Carbon storage, also one of those important issues in the ATEAM project.
At the moment Europe is a carbon sink, net of vegetation stores carbon.
But with increasing temperatures that sink weakens.
So the strength of carbon uptake is reduced.
Yes, we have positive effects of the increase in forest area,
but you have some negative effects of climate change in there.
Water, also a very interesting sector.
So there's again a strong change in regional patterns in Europe.
The run off decreases in southern Europe and increases in northern Europe.
We will have more severe drought and at the same time also some extreme floods.
People who don't have adequate water supply actually increase.
And very important if we look at some of the storage,
the buffering of water in our mountain systems, the snow melts, snow melts earlier,
and you actually get much more rain driven events in your water system
than the very strong seasonal part which comes from the mountains.
So you get shifts in time.
Biodiversity, there we actually looked at very much the plants and the insects,
very many different species, and looked at their current habitats and how these habitats changed.
And there you again see very clear vulnerabilities of mountain areas.
Species climb up the mountain when it's getting warmer,
but the mountains are unfortunately not high enough, so they drop off at the top.
The vulnerable systems are very much the Alpine systems,
but also the Mediterranean regions where the drought really takes its toll.
And of course if you look at biodiversity on adaptation
you immediately start thinking about nature reserves.
But because of all those shifting vegetation patterns
nature reserves is actually not a very good tool to deal with changes in biodiversity.
Nature reserves have a boundary, a legal boundary,
and you actually have to shift that when plants and species start to shift as well.
So that was very much the ATEAM project.
It was published five years of research in a five page paper in Science.
Very much that the European drivers differ from some of the global trends.
You have very strong regional patterns in Europe.
Changes in land management actually can make the impact of climate change worse or can help to adapt.
The different scenarios we used,
which were the IPCC storylines, they don't have an optimal pathway.
All have their specific problems.
The B1 scenario was relatively benign, but that focused also very much on sustainability.
If we look at vulnerability the Mediterranean regions,
the mountain regions were very much the most vulnerable within Europe.
That was partly because of limited adaptive capacity.
And if you really start looking at adaptation you have to take the stakeholders into account.
You have to look at the interplay between the stakeholders and the environmental factors.
And there again, the European policies,
the national policies and the local policies have to be taken into account.
And that actually contributes to the heterogeneity of the different responses.
These kind of studies, you do it on a scientific basis,
but you have to communicate them to policy makers.
And you can do that at the local level,
you do it with some of the stakeholders like farmers or fishermen,
so like the picture here in Ghana, or at the big conferences.
And you have to look at the science.
And you have to deal with some of the uncertainties in the science.
And this diagram actually depicts some of the uncertainties.
For example, there is the level of agreement or consensus.
If you have a scientific debate and that debate converges into consensus,
people start to agree, then that becomes higher.
And then you have the amount of evidence. Evidence can be independent.
You can get evidence from observations, from experiments, from theory, from models.
There are many different tools you can use in science to actually get different evidence.
So if your evidence increases but you still have a lack of consensus you have competing explanations.
If you have no evidence, no consensus, it's speculation.
If you have little evidence but quite a strong consensus,
it's established, but the science is actually incomplete.
And only when you have a lot of evidence, and a lot of consensus actually people agree.
If I take this little thing and open my fingers, what will happen? It will fall down.
We know, we have gravity, the bigger volume of the earth attracts the smaller volume of this little device.
You have done that experiment hundreds of times slipping things from our fingers etc.
With gravity that's very much well established science.
But in the whole discussion of impacts and adaptation,
partly also because that science is often policy relevant,
but policy relevant is future oriented and not past oriented.
So it sits in the other boxes. And you have to be honest in actually assessing that.
And that's very much done within the IPCC.
And the IPCC is a big body of scientists coming together,
discussing and trying to actually look at the evidence and provide the certainty,
the uncertainty, the established type of science.
And if we look at the last assessment
and actually the next assessment will come out later this year and next year,
the messages in that one are probably also again stronger,
but the assessment looks at the scientific basis, one report,
the impacts, adaptation and vulnerability,
the second working group, and the mitigation a third working group,
and then a summary in the synthesis report.
This is about 3,000-4,000 pages of assessing the scientific literature.
And here it is just summarised in three bullet points.
The report says the warming of the climate system is unequivocal now.
We see it, we observe it. We see it in many different systems in many different places.
And most of that increase in temperature since the mid 20th century is very likely,
and very likely is more than 95% probability,
very clearly defined within the IPCC,
due to the observed increase in anthropogenic greenhouse gas concentrations.
And then from the other working groups there's very high confidence
that neither adaptation nor mitigation alone can avoid all the climate change impacts.
But together they can reduce the risk.
Now this was 2007, since the emissions have been increasing,
the concentrations have been increasing.
And there have been statements that although we often see adaptation and mitigation as a balance,
if you don't mitigate you have to adapt, you have to cope with some of the impacts.
But at the moment we see that there are limits of adaptation.
If we move to three, four degrees of worldwide warming can we adapt to that?
It's a big question mark.
And John Holdren, Obama's Chief Science Advisor, recently actually said
there's a gap between adaptation and mitigation.
And he labelled that gap with the name suffering.
So that's really where we should be dealing with.
Now if we look at the IPCC report when it came out, it's again communication of science.
This is a Dutch newspaper article. It's an excellent article.
It gives an excellent summary. Now you can't read it, the print is too small.
But the headline said it's a dramatic report without an alarmist tone.
And if we then see what the journalist does, it takes the polar bear.
They are a vulnerable species, in a very alarmist picture.
It takes a dike breach in the middle of summer because of drought in the Netherlands.
It takes major flooding and drought and the snow on Kilimanjaro.
So although the headline and the summary is a very fair representation of the report,
the pictures actually give a completely different picture.
And so where is the balance?
Is that science or is that really the media which are pushing the different things?
And of course after the fourth assessment report there were some mistakes.
There were major criticisms.
And these mistakes just before the Copenhagen Conference were very strongly blown up.
There was mistakes on a statement in the Himalayas.
Yes, there were mistakes in the procedure and the reviews.
One reviewer actually notified that mistake, but the authors didn't do anything about it.
So there was a whole set of discussion. And IPCC was put into discredit.
And you saw a lot of cartoons with Pachauri - it's all lies, we don't have mistakes.
And if you see how IPCC actually dealt with it, it was also not that …always that elegant.
But also if you look at the science, if you look for example at the temperature records.
And here are some of the temperature points of the last 40 years.
You can actually look at selections and say, OK, temperature is not increasing.
And some of the climate deniers make us believe that temperature is like a staircase.
The steps are flat. And all steps are flat so there's no increase.
But a staircase actually goes up.
And if we look at the data, the 80s were warmer than the 70s, the 90s were warmer than the 80s.
The first ten years of this century were warmer than the 90s
and it's increasing if you look at the longer term averages.
And that's also very clearly seen if you look at the longer term records.
And you look, if you want to explain it, that's one of the pictures from the IPCC
where this is the observed temperature records,
there is actually a whole set of model runs in blue,
where the models only take the natural vulnerability.
They don't assume the increase in CO2. Then the temperature is actually relatively flat.
With CO2 you follow the observed temperature.
And that's one of the reasons that the IPCC also said,
very likely due to the increase in greenhouse gases.
You also see a series of studies over the last two years
which actually try to attribute the changes in temperature.
And this is a study by Stefan Rahmstorf from the Potsdam Institute of Climate Impact Studies
where he took out all the natural vulnerability, the impacts of volcanoes,
the impact of el Nino, the impacts of solar variation
and actually got quite a strong rising trend with the warmest years really the last few years.
We still see there's a lot of variability which is not explained.
But the level of temperatures are actually increasing.
And if you look at the whole discussion with the climate deniers and a series of reports the science,
these reports from different academies from some of the commissions of government
really look at the science as being very honest and correct.
But not everybody believes that it's a white wash.
But the reports speak a very very clear language that we have to trust the science of the IPCC etc.
But not everybody believes it.
Some people like this Republican, John Shimkus, really say the Bible says there won't be big floods anymore.
So climate change cannot be a problem. That's like an ostrich, very very strongly.
Now what we do with the Earth Systems Science Partnership is actually trying to inform the policy makers.
And this is a lecture I gave with the title - What's dangerous climate change? – for the Convention of Climate.
And there we summarise some of these impacts.
And one of the impacts is an increase in CO2, which is taken up by the ocean.
You get the whole carbonate chemistry.
And it leads to acidification of the ocean.
Acidification of the ocean has a large impact on all calcareous organisms like corals.
We talk about the changes in biodiversity.
Climate change is one, or will be soon one of the major threats to biodiversity,
stronger than changes in habitats.
We looked at trends in CO2 emissions, and the trend is still increasing.
Yes, in 2008 we had worldwide a wonderful policy to reduce the emissions.
It was called the financial crisis, but afterwards the emissions actually picked up again.
But the interesting thing, if you look at the emissions,
is actually that a lot of people now say, look at China.
China is growing very fast, together with India, together with Brazil.
But if you look at the emissions of China, it's actually most of the emissions of China,
about 40%, are in products which are consumed either in Japan, in Europe, in Australia or North America.
So are the Chinese emissions our emissions or their emissions?
Within the U.N. system they are their emissions because they are emitted in China.
But if you look at a more systemic approach it's actually our emissions.
And so you really have to start not pinpointing at countries,
we have to start to solve the problem together.
And then of course in this lecture we also talk about the science update, the mistakes in the IPCC.
And if you look at the problems in the Himalayas at the moment with some of the lower glaciers which are melting,
and the glacier lakes which actually provide flooding to villages,
there is a problem, which has to be dealt with by these local people.
And if we look at some of the other impacts we actually see the last few years
a very big extent of melting of the arctic sea ice.
And last year was the smallest extent ever observed by humans.
But industry is immediately taking advantage of that.
Last November I saw a big announcement that you could take a cruise, €15,000,
going from Greenland through the Northwest passage to Alaska this September.
So in principle they already think there will be less ice and it will be opened up for cruises.
They are very very difficult to navigate.
What will happen if there is an accident etc. etc.?
But it's happening, people are taking advantage.
You also see the impact increasing temperature of ocean waters.
That's partly influencing sea level. It's partly influencing also the melting of the ice.
And it's part of the energy and the heat budget of the world.
And we see the sea level rise.
And sea level rise has been controversial,
because we measure it at several points in different countries.
But recently, over the last ten years,
we have satellites which very precisely measure the altimetry of the oceans.
And they do that every month and have a very much global coverage.
And it's these satellites which actually give a very very precise picture.
And with the satellites calibrated with the land based…
the coastal based measurements we really see that sea level rise at the moment is increasing.
But we also see, with the satellite, a very interesting picture.
The sea level is not level. There are very big regional and local differences.
And we heard the stories of some of the islands in the Pacific ocean
which are already very very vulnerable.
And some of those areas in the Pacific ocean actually sea levels rises two metres higher
than in other areas where it is lower.
So there are also waves, etc., partly because of gravity,
but there are strong regional differences in there as well.
So if you look at what we know of climate change,
the mainstream science of climate change, the conclusions are very very firm.
Human activities are the main cause of the increasing concentrations of greenhouse gases in the atmosphere.
And that's the main cause of the observed increase in temperature over the last few decades.
The physics are very well understood.
Now Tyndall was mentioned, he actually established part of those physics.
And it hasn't been challenged ever since.
The climate projections are coming true.
And the first climate projections were made in the 70s.
More advanced ones in the 80s. The first IPCC scenarios came in the 90s.
We are actually seeing very much the trends which were predicted 10, 20 years ago.
And many of the sceptical arguments have been refuted,
by many many scientists, many different reports.
And some people say that it is the science.
But the science, the review, bad ideas are refuted, the science is very much self-correcting.
So the body of science is actually very very clear.
So if you look at the policies, reaching this two degree target,
which was agreed upon in Copenhagen.
Now if we look at the models, if we look at the carbon cycle,
of all the CO2 that we emit and the other greenhouse gases,
but if you only look at CO2, 50% of that CO2 which we emit into the atmosphere
is taken up by the oceans and by the world's vegetation.
Now that's a very big service, otherwise the CO2 would increase much much faster.
But with an increasing temperature, increasing ocean water temperature the ocean will absorb less CO2.
And also the sink in plants will decrease. So it's finding that balance.
And if you really want to reach the two degree target,
if you are looking at the budget,
then actually the CO2 which comes into the atmosphere must be equal as what goes out of the atmosphere,
the same as your own wallet.
Your saving must be the same as your income
if you want to keep the same amount of capital in your wallet.
So it's a budget calculation.
And if we look at the emissions, these are increasing,
if we look at the concentrations which is actually the amount of CO2 in the atmosphere,
you really have to reduce the emissions by at least 60%, 70%,
to actually get a stable set of concentration.
Then the emissions are the same as the uptake by the oceans and by land.
That was shown strongly in a conference we had last year with the Global Environmental Change Programmes,
where we looked again at all the evidence and really stressed the urgency.
But we also looked at some of the solutions.
And yes we have a lot of technical solutions.
Yes, we have a lot of possibilities, but also the attitudes, the behaviour, development has to be taken into the equation.
That was very strongly stated in a statement in the Planet Under Pressure Conference.
Recently in November the World Bank put out a report, Turn Down the Heat.
They were looking at if we don't reduce the emissions soon then we will actually get a world of four degrees.
What does this mean?
They looked at the observed changes and the impacts, the rising CO2 concentrations,
sea level rise, human support systems, four degrees really jeopardises food security,
water security, and a whole set of ecosystem services and human health issues.
And you will get because of some of the extreme events,
like we have seen with the storm Sandy last November,
you get a lot of disruptions and maybe also a lot of climate refugees.
And this report was actually quite well received.
Ban Ki-moon made a very strong statement that the science is sound we have to start acting now.
And your former Prime Minister, Mary Robinson, really looked at the report and said,
we have to put that into discussion with development.
So this report was actually quite influential.
But what is the issue? The issue is actually very much the emissions.
The emissions are increasing.
If we want to reduce the emissions two degrees actually they have to go down,
but if we wait they have to go down steeper.
So the longer we wait the more effort we have to do.
And that's partly called the emission gap.
And bridging that emission gap, another report by United Nations Environment Programme,
they actually looked, how do we get from here to very much that low level.
And if we look at all the measures, all the sectors,
all the different people, all the different countries have to actually provide their contribution.
And recently a different approach was proposed.
They didn't look so much at the budget but they looked at cumulative emissions.
And the cumulative emissions are the amount of emissions,
in principle the surface under these kind of curves.
And if you look the amount of carbon we could release into the atmosphere in the coming 50 years
then if we do that with 1,000 gigatonnes that would give a 50% probability to stay within that two degree target.
If we go higher then you actually get much higher climate change.
But here the elegant part of this graph is actually if you look at the 1,000 gigatonnes,
at the moment we have already emitted 600 of the 1,000.
So there are 400 left to stay within that two degree target.
How do we divide that 400?
Are countries like the developing countries,
China, Brazil, India, because they haven't emitted so much in the past,
can they take the biggest share?
We as industrialised countries are the most addicted to energy.
And because addiction is very difficult to move away from,
do we have the right to the biggest share?
So it's very much an equity issue.
How do we share in the coming 40 years that 400 gigagtonnes of carbon?
And the current emissions is very much about 10 gigatonnes per year.
So if you don't have growth it's 40 years of emissions.
Now how can we reduce those emissions?
Very very simple. It's increasing energy efficiencies.
Very much looking at warming and cooling in houses, looking at transport.
Don't have big cars, but smaller lean energy cars.
And being Dutch I of course have to push the bicycle as very much a zero carbon vehicle.
And actually in cities it's much much faster than most cars.
We can also increase the carbon efficiencies by moving away from coal
which is very dirty from a CO2 perspective to natural gas….to oil, to natural gas, or to renewables.
And there's a whole set of different renewables.
We have to start reducing deforestation.
But we look at deforestation, the emissions of deforestation actually, unfortunately they are going down.
And we can…our forests, we can sequester carbon, but that's also limited.
In principle those first two increasing energy efficiency and increasing the carbon efficiency are the most important.
Also 10% of our emissions come from cement.
If we build more wooden houses, we use the forest, we use them more sustainably etc.
and every tonne of cement in principle is a tonne of CO2.
And finally we have to look at carbon capture and storage.
If we want to have big fossil fuel power plants don't let the CO2 go into the atmosphere.
Capture it and store it somewhere underground in old gas fields etc.
It's expensive, it decreases some of the efficiencies,
but it is one of the measures which should be implemented.
If we look at the emission curve we very much see an increase.
And that's the financial crisis in 2008, but the emissions have picked up quite strongly since.
And when we see in the 90s an increase in emissions of 1% a year,
over the last five years we actually see a 3% increase per year, very very strong.
3% increase per year means doubling of emissions every 20 years.
And that has a strong effect on the concentrations and thus the climate change.
And within the coming five years we have to start to peak the worldwide emissions and then they have to go down.
And the IPCC scenarios have gone through a new development.
There's a whole set of new scenarios being developed at the moment.
And here is a picture of those. And there's where you see the emissions.
They actually follow the highest scenario, which leads to four to six degrees of warming.
There's one scenario which is actually the lowest scenario, after 2075 it has negative emissions.
That's the scenario which keeps us within the two degree target.
So we are not on that path of the blue.
And if we wait reducing the emissions actually the way down has to be steeper.
And if we look at the discussion of are scientists alarmist I think this picture is quite illustrative.
These are all the different scenarios of the IPCC.
The first scenarios in the first assessment report in the early 90s,
the IS92 scenarios, the SRES scenarios, and the current RCP scenarios.
And if you look, you plot in the actual observed emissions
they are always at the higher end of the scenarios.
So the scientists actually have been more optimistic than reality.
And so we are at a very very high part of these kinds of emissions.
And the pathway of change we really have to make that conversion to the blue line.
Now initially that's reversing our track,
moving away from fossil fuels to renewables,
strongly increasing the energy efficiency, trying to peak worldwide emissions by at least 2020.
In the medium term we have to sustain that improvement of emissions.
So the emissions go down further, about 3% per year to keep on that two degree target.
And in the long term because historically we have had these emissions,
you actually have to start looking at negative emissions.
That's planting forests, that's carbon capture and storage,
that's a whole set of new innovative technologies.
But we all know that if we want to innovate, innovation takes time.
You have to do the research, you have to put the implementation,
you have to get the economics right, etc. etc.
So how probable that scenario is that we actually start moving to that blue line
I really think that's part of the urgency.
We have to stress to our policy makers that they have to start to hurry.
The problem was known already in the early 90s,
was quite strongly established with discernible influence in 1995,
but the policy makers have not taken their responsibility with the very obvious scientific signs.
Thank you very much.
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Prof. Dr. Rik Leemans, Environmental Systems Analysis & Earth System Science Groups Wageningen University
A Time for Giant Steps