"We are not on the right trajectory at all. The good news is that all options are within our reach, but a radical transformation is required."

JS: What this report shows us is that we are not on the right track at all. Emissions are still rising and if we do nothing, 1.5°C will be reached within 10 years. On the other hand, the other key message of the report is that all options are within our reach. A complete transformation is needed, but it is entirely possible!

It must be done at three levels:

Firstly, on the energy front: we absolutely have to switch to renewables. The good news is that prices have fallen dramatically. They are now competitive with fossil fuels and in many cases lower.

Secondly, agriculture and land use: We need to change our agricultural system and therefore our diet. In other words, we need to switch to a healthy and sustainable diet, mainly based on plants. This does not mean that meat and dairy products are to be excluded completely, but they will be much rarer. This obviously affects emotions, culture, different economic sectors, but we have to go through this.

Thirdly, energy demand, which is the big news in this report: for the first time, we are no longer saying that it must necessarily continue to increase. On the contrary, there are many options for reducing this demand considerably, be it through technology, infrastructure or possible social modes of operation.

It has even been shown that a healthier society with less air pollution, less noise and other negative effects can result. A transformation of the living environment therefore does not necessarily endanger our social well-being and can be experienced in a very positive way. 

JS: The question of how to bring about these transformations at the socio-economic level is addressed in the last chapter. It shows the importance of citizen involvement. There are already cities and neighbourhoods here and there that are concrete technological examples, but what is needed above all is to offer a vision that makes people want to move in this direction.

It must be done at the level of consumers, households, industry and labour. But the most important thing to remember is that it can be done in absolute harmony with the well-being and social progress of people at the global level.

What also stands out and is very strong is the link between climate action and the UN's sustainable development goals: "Without ambitious climate action, sustainable development will not be possible. We do not only see that climate action is compatible with sustainable development, but above all that without climate action, the dimensions of sustainable development (which include poverty, hunger, equality, health) will be increasingly difficult to achieve, if not impossible.

JS: The first part of the report focuses on the earth system, physics, chemistry, biology, to understand how global warming is occurring and how we are disrupting the system.

The second part deals with impacts. Global warming is one thing, but there will be many other impacts that will affect human populations. It is a question of analysing how this transformation of the earth system is affecting agriculture, the oceans and to what extent it will have an impact on food, health, ecosystems, biodiversity and everything else that affects our societies. This is what we call adaptation, i.e. the mitigation of these impacts.

Let us remember that there are two types of mitigation: mitigation of global warming itself and mitigation of the impacts. The question is simple: is it possible to put in place strategies to survive the impacts? Let's say we start planting species that are adapted to the climate we expect in 10 years' time rather than the current one. The climate zones are moving much faster than the trees can adapt.

Another strategy would be to have architectural codes that protect people from heat waves. For example, we should never put windows facing south, have green balconies, and break up hard surfaces as much as possible and put in trees to cool them down. 

To deal with this, we have to break up the hard surfaces, all the roads, car parks, it's catastrophic, the water has to be able to infiltrate into the soil, this implies making the built environment more porous and capable of accommodating these huge water discharges.

So these are examples of mitigation, but more importantly, Working Group II has shown that there are limits to adaptation. Developing strategies that can cope with 1.5°C is already difficult. At two degrees, we really reach the limits of our ability to protect ourselves. Group III starts from this observation and goes further: how can we transform our societies to stop emitting greenhouse gases?

There is no longer any justification for investing in the fossil fuel sector. It is an industry that is doomed to disappear and that, if we want to stay below 1.5°C, will have to be stopped prematurely. Millions and millions of dollars of investment will be lost, and that's what it's all about.

One could argue that by producing a lot of negative emissions, we could afford to continue emitting fossil fuels, but these options are actually minimal. Today, our concrete options are: stop fossil fuels right now, reduce demand, move forward with renewable energies and change our agriculture and diet. We have a lot to do and very little time.

JS: Indeed, the issue of consumption, but also of under-consumption, is addressed in a more direct way. It clearly shows that there are billions of people on the planet who are in a situation of energy poverty. On the one hand, they do not have enough to eat, but more importantly, they do not have the infrastructure or access to energy services to live properly in our societies.

Not having access to air-conditioning is something that in the long run can kill people or cause illness. Not having access to modern energy sources such as electricity means burning wood at home on very inefficient and polluting infrastructure.

We have the technologies to address under-consumption without blowing the carbon budget or increasing energy demand. This is incredibly positive.

This report also talks about over-consumption: consumption that does not serve human well-being. Take transport: big cars, air travel, all this is distributed extremely unevenly, with 20% of the population emitting 80% of emissions even within industrialised countries. In the UK, half the population never fly.

Along with Working Group II, this is one of the first reports to question the dogma of economic growth and ask: do we need growth or can we move to something more along the lines of post-growth or degrowth?

More about the expert:

Julia Steinberger is lead author of the IPCC Sixth Assessment Report (Working Group III - Climate Change Mitigation, Chapter 3), UNIL professor and academic co-director of CLIMACT.

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