Abandon cars, reforest woodland, eat more veggies – what must humankind do immediately to stop global warming? This is what nine leading researchers told ZEIT ONLINE.
We can't go on like this. If the Earth warms up by more than 1.5 degrees Celsius by the year 2100, the consequences will be serious and irreversible climate changes will be set in motion, as the latest special report from the United Nations Intergovernmental Panel on Climate Change (IPCC) shows. From Dec. 3-14, politicians and government representatives will once again discuss at a climate conference how the 1.5-degree target can be achieved.
We asked nine leading climate scientists to imagine if they were the sole ruler of the planet, what they would do to limit global warming if they could make a unilateral decision and didn't have to resort to negotiations, political wrangling or compromises. What immediate action would you take?
"A CO2 Tax Makes Technologies Such As Wind and Solar Power Competitive"
Brigitte Knopf is the secretary-general of the Mercator Research Institute on Global Commons and Climate Change (MCC) in Berlin.
I would no longer let countries, companies and citizens emit carbon dioxide (CO2) for free and would instead immediately introduce a price of 50 euros for every ton of CO2 emitted. This would hold everyone responsible for the negative effects of fossil emissions, which include climate change, air pollution and health problems. A CO2 tax would have three effects: First, it punishes the consumption of coal, oil and gas according to their carbon content. Second, it makes CO2-free technologies such as wind or solar power competitive and drives new investments in that direction. Third, it generates revenues for governments, which I would redistribute on a per-capita basis. This would protect poorer households in particular from higher energy prices and ensure a just transition. MCC research shows that even a low price for CO2 could finance universal access to clean water and sanitation in many countries (Nature Climate Change: Jakob et al., 2015). This would make climate policy a success story.
"New Industrial Plants Should Be CO2-Free By 2025"
Niklas Höhne is the director of the New Climate Institute in Berlin and a professor at Wageningen University in the Netherlands.
To keep the climate at safe levels, global greenhouse gas emissions must be reduced to zero in all sectors and countries. This is why I would prescribe, that everything that is newly built should be emission-free. From now on, for example, only power plants that use renewable energies should be built, not new fossil fuel power plants. From the early 2020s, only electric cars or cars with other CO2-free engines should be sold. And new industrial plants should be carbon dioxide-free by 2025. The clear time horizon as of when only zero emission technology can be sold would drive the necessary innovation. In addition, I would implement a tax on greenhouse gas emissions to collect financial resources to compensate for potential negative social effects of this rapid transition, eg. in regions that are currently dependant on coal mining or use.
The currently implemented climate policies with the highest impact follow this model even if initially implemented by only a few. For example, the first electric cars suitable for series production were developed because the U.S. state of California introduced a quota for zero-emission cars in the 1990s (CARB ZEV). With minimum quotas for the new registration of electric vehicles, China is also forcing car manufacturers to expand their product range, which will then be sold globally. Another example: Wind power, which was mainly subsidized in Germany, is now being used worldwide – even in countries that previously did not have an interest in it before, such as China, India and Australia, due to their large coal reserves.
"All Countries Should Take Stock of the Damage"
Friederike Otto is the acting director of the Environmental Change Institute at Oxford University in England.
Think of the forest fires in California in November of this year or on a less dramatic level the heatwave in Germany and the EU this summer. The methods available today allow us to attribute such events to human-induced climate change (Annual Review of Environment and Resources: Otto et al., 2017). At present, however, we simply have no idea about the damages and losses caused by climate change to date. It is difficult to solve a problem that is vague and often assumed to be a future problem only. All countries should therefore develop an inventory so that we can effectively see the costs of climate change.
New Zealand has shown the way: Floods and droughts caused by man-made climate change currently cost around $120 million per decade (New Zealand Climate Change Research Institute and NIWA, 2018, PDF).
Hermann Lotze-Campen is a professor of sustainable land use and climate change at Berlin's Humboldt University and chair of Research Area II "Climate Impact and Vulnerability" at the Potsdam Institute for Climate Impact Research.
About 25 percent of annual global greenhouse gas emissions are attributable to food – especially meat products (Climate Change 2014: Smith et al., 2014). We should therefore all immediately adopt the "10 Guidelines of the German Nutrition Society (DGE) for a Wholesome Diet" – and nourish ourselves with a healthy mix of food that includes a high proportion of fruit and vegetables. This helps to prevent obesity and high blood pressure, it would slow global warming and it would significantly lower the nitrogen pollution in our groundwater. This is because most nitrogen is produced in agriculture to grow feed crops for animals or comes from animal manure (The European Nitrogen Assessment: Sutton et al., 2011). People in rich countries should reduce their meat consumption to 600 grams per week as soon as possible and to 300 grams per week later: For Germans, this would mean first cutting meat consumption in half and then reducing it to two or three small portions a week. At the same time, I would double the research funding for plant-based alternatives to meat.
"We Need Public Transport and Better Teleconferencing"
Gabriele Clarissa Hegerl is a professor of climate system sciences at the University of Edinburgh in Scotland.
I would create reliable, fast and convenient public transport, so that short-haul flights are unnecessary and many more people can commute by public transport. Another very practical measure would be to improve teleconferencing. This could help us to avoid many short-haul journeys and flights, which in turn would significantly reduce our CO2 footprint. Avoiding air travel altogether is one of the most effective measures for significantly reducing an individual's greenhouse gas emissions (Environmental Research Letters: Wynes and Nicholas, 2017).
"Our Biosphere Must Be Protected To Store Carbon"
Yadvinder Malhi is a professor of ecosystem science at Oxford University in England.
We must preserve and restore our ecosystems to store and absorb carbon, to regulate local and regional rainfall, and to maintain a moderate climate. Our forests and soils contain significant amounts of carbon, so deforestation has a direct impact on our climate. Tropical regions, for example, are the engines of atmospheric circulation. The loss of rainforest, which is transformed into cattle farms or oil palm plantations, also affects distant regions such as Europe, Siberia and North America. It also has an indirect effect on rainfall and cloud formation. Clouds, in turn, reflect sunlight and cool our planet. Our actions do not only have local consequences, the scale of our activities is much larger.
We also need to think more about restoring forests and other ecosystems in the heavily transformed landscapes of Europe. We must protect intact areas and change our policy incentives in the north to restore forests on abandoned or marginal farmlands. Nature is not an external cost factor that can be included in or omitted from our economic model. Nature is one of our most important allies in reducing the scale and impact of climate change.
Angelika Hilbeck is with the Institute for Integrative Biology at ETH Zurich in Switzerland.
Most of the food we buy in supermarkets comes from industrial agriculture, especially in developed countries, but increasingly worldwide. This form of intensive farming is based on chemical inputs and practices that are energy-intensive and harmful to the environment. According to the IPCC, it contributes to more than 20 percent of global human-caused greenhouse gas emissions (IPCC, Working Group III: Mitigation, 2014). We must therefore use agro-ecological production systems instead. This means applying ecological and social concepts in food design, changing farming practices and following these principles in our agricultural systems.
Another consequence: With improved agriculture, we preserve biodiversity, the fertility of our soils and contribute to feeding humanity. The UN Human Rights Council reported this in 2010. Our agriculture can thus become part of the solution rather than a problem that contributes to climate change.
"Products Should Be Labeled with CO2"
Per Espen Stoknes is the author of the book "What We Think About When We Try Not To Think About Global Warming: Toward a New Psychology of Climate Action."
All products and services worldwide should be marketed and sold with clear labeling of their CO2 emissions and their environmental footprint. The life cycle of the product should be fully understandable to the consumer. Whether the product has a positive, neutral or negative footprint should be as prominent as the purchase price. And it should be easy to understand where and how the products were made and who made them. This could be possible, for example, with blockchain databases that trace and store the data and path of the product. This would make it easy for customers to choose greener products in all markets and prevent products from being advertised with a sustainable label without clear evidence. Greenwashing would no longer be possible.
"We Need Politicians To Represent Our Interests"
Michael Mann is the director of the Penn State Earth System Science Center in University Park, Pennsylvania.
In the United States, we currently provide more subsidies for fossil fuels than for renewable energies. This is the opposite of what is required. We need politicians who represent our interests rather than fossil fuel interests. At the moment, the U.S. federal government is led by the latter. My wish therefore goes to my fellow Americans who believe that we have to act on climate change: Make your voice heard. An effective solution must include both personal action and government policy. But the former can be encouraged by the latter, so we must focus on policy intervention, which includes electing climate-friendly politicians. That’s the single most important thing we can do right now.