Interview with Edward Rubin: “What we see today is a small taste of what may be coming in the next decade and beyond” 

Less than ten years away from the deadline for achieving UN Sustainable Development Goals, we are still far from having food systems that are in complete harmony with ecological needs. We discussed this issue with Edward Rubin, a winner of the 2007 Nobel Peace Prize for his work on the Intergovernmental Panel on Climate Change (IPCC) and current Alumni Chair Professor of Environmental Engineering and Science Emeritus at Carnegie Mellon University.  

— Nature is speaking. Are we listening to it? 

— “Some people are listening very carefully and others not so much. The scientific community listens and understands the issue very well. The public at large I think is increasingly aware of the problem of climate change. Surveys show that people understand it is here now and something must be done about it. The key question is what exactly should be done? What are we willing to do now? 

Unfortunately, the situation today is largely one of weak actions and delay. Despite a lot of encouraging words and promises, most countries are failing to meet even the modest commitments made under the international agreement to limit global warming. With a few notable exceptions, delay as the new denial is perhaps the most apt way of describing the current political environment in many countries.” 

— Climate change is seriously affecting agrifood systems and viceversa. 

— “The effect of climate on agriculture is very straightforward. All crops need the right amounts of sunlight, moisture, and temperature. If it is too hot or too cold, they won´t grow. The climate has similar effects on fish and meat production. But what is less obvious is the effect of the food system on climate. Agriculture, for example, is not just growing crops. You also have to harvest, package and transport food to people. Then at the end of that process, we throw away a lot of food. 

When you look at the entire food system, everything we do directly or indirectly results in greenhouse gas emissions. Maybe the most obvious example is food-related transportation. We use trucks to deliver food from farms to warehouses and from warehouses to stores. Then we have additional transport each time we drive to the supermarket or to a restaurant. All of this releases greenhouse gases from the fuels burned for transportation. 

At the front end of the system, the production of crops, meat, fish, beverages and other foods involves processing and packaging that result in additional greenhouse gas emissions. Another less obvious source of emissions is the energy that we use to store food and keep it fresh. Freezers and refrigerators consume large amounts of energy when you look at the big picture. Today, most of that energy comes from burning fossil fuels”. 

— It is evident the overall impact is huge. 

— “I was surprised the first time I looked at the urban food system to see how big the overall impact is. With a class of students at Carnegie Mellon we analysed the carbon footprint of the Pittsburgh food system. We found that it contributed nearly 30% of all greenhouse gas emissions in the region. Published studies of other regions found similar results.” 

— If we don´t put a halt to the climate crisis, what we will end up putting on our plates? 

— “The effect of climate change on food systems will depend heavily on the economic well-being of a country, region, or family. People at the bottom of the economic ladder are more vulnerable to the impacts of climate change. If you look at the history of human civilization you see that entire communities often disappeared when climate impacts like floods and droughts, coupled with poor land use practices, left them without a reliable source of food.  

Today we see similar things happening in some parts of the world. Looking ahead, what we see today is a small taste of what may be coming in the next decade and beyond.  

The IPCC has assessed the vulnerability of different world regions to climate change impacts, including on agriculture. Even wealthy countries are vulnerable. Studies for Europe, for example, estimate up to a 25% reduction in major crop yields in Spain under a ‘business as usual’ scenario along with unexpected production losses from extreme weather events.  Is that a food security issue? I think it is.” 

—It is clear we should modify our food systems in order to make them more resilient and efficient. How can we get there? 

— “We have known for a long time what we have to do to reduce climate change impacts on the food system. In some cases, this means developing more resilient varieties of crops, or changing the mix of crops in a particular region. In other cases, resiliency comes from more efficient use of scarce resources such as water. For example, to reduce water use for irrigation, wine makers in California have been employing sensors to measure the soil moisture content throughout large fields to identify dry areas to irrigate only when and where it is required. That is one example of where advanced technology is being used to improve efficiency and resilience. 

 The related need is to reduce the carbon footprint of the food system to help prevent dangerous levels of climate change. This requires that we have net zero emissions globally by mid-century, not far from now. That means that any CO2 put into the air must be offset by other measures that take it back out, such as by planting trees, better agricultural processes and other techniques. This does not necessarily mean we have to radically change the food system. But it does mean that we have to find ways of reducing the production, consumption and waste activities that contribute most to the carbon footprint. 

For this effort to succeed, institutional backing from the private sector and the responsibility of individual consumers will be essential. This is where government programs and policies also are needed to speed up that process, including support for education and innovation.”  

—The Spanish government has recently passed a law to fight against food loss and waste. The involvement of the public sector is important. What about the responsibility of individual consumers? 

— “That kind of initiative is a great example of what we need at the moment. When you look at the numbers, the food production system is the biggest source of greenhouse gas emissions. So, the less we consume, the smaller the problem. Meat production is by far the most carbon-intensive source of emissions, so modifying our diets to reduce meat consumption is the first place to start. The second biggest area is waste, which is the target of the new Spanish law. In the United States, for example, roughly a third of the food supply ends up in the garbage. You see this every day in restaurants, stores and at home. This waste requires additional transportation to a disposal site such as a landfill, where still more greenhouse gases are produced as the waste decays. So, every ton of waste we can eliminate reduces emissions across the whole food system. Clearly, individual consumers have a major role and responsibility here. 

Reducing the energy needed for food storage and transportation also demands a careful look at the sources of food supply. In Pittsburgh, for example, we found that much of the food that is consumed comes from thousands of kilometres away.” 

— This is where the importance of eating local food comes in. 

— “The benefits are that you reduce transportation needs, you support the local economy and you have a better idea of the quality of the food. Small local food producers can also have the advantage of doing things that larger organisations are not interested in doing, or willing to do, to maximize efficiency and minimize waste”.  

— Is there any message that you would like to spread? 

— “We already talked about things we can and should do as individuals to reduce our carbon footprint and climate impacts. But to me, the most important thing we can do in democratic countries is to elect people in government who support and work for climate change actions. Become knowledgeable about political candidates and their views on climate change. Elect people who support climate action and fire people who don’t. That would be my message.”