Getting to Net Zero requires a systems approach

You’re an expert on agronomy and agriculture. Many people, when they think of sustainability, typically think of the need to clean up “smokestack industries” that emit a lot of pollution. Where does agriculture fit into the sustainability picture?
Agriculture, forestry and other land use (AFOLU) is responsible for about 23% of all greenhouse gas emissions globally. Although this is an alarming figure, this sector can become part of the solution to tackle climate change because it can provide carbon removal in forests and soils. For example, regenerative agricultural systems usually increase soil carbon and biodiversity, whereas large-scale monoculture plantation schemes can be detrimental to biodiversity, water, and soil conservation in the long term.

Another example is sustainable bioenergy (from biomass, such as wood pellets, biofuel crops, and agricultural residues), which can substitute part of our fossil-fuel consumption. In addition, bioenergy can be associated with carbon capture and storage systems, providing net negative emissions, i.e., a net carbon dioxide removal from the atmosphere, instead of only reducing emissions. Therefore, looking at this sector from a systems perspective is fundamental.

Nature-based solutions are an interest of yours. Are these mainly related to conservation – soil, coral reefs, etc.? How do they fit into the larger effort to limit climate change?
This concept is based on the idea that some environmental solutions can be addressed through natural processes if we work towards resilient systems and increase carbon sequestration via photosynthesis. For example, when we convert degraded lands into forestlands, there is an increase in the carbon content in the above-ground biomass and soil carbon, as well as an increase in water retention and biodiversity. Another example is the integration of agriculture, livestock, and forestry, such as agroforestry systems, which can increase total productivity and biodiversity, reducing the need for pesticides and land resources. Nature-based solutions should be addressed as part of a broader bioeconomy strategy, including food security, bioenergy, and forest conservation, respecting traditional communities' rights.

On the other hand, nature-based solutions have scale limits and are subject to temporal uncertainties and vulnerabilities, such as droughts, wildfires, and land use change. They are not a panacea. We should also increase the share of renewable energies globally, transform our cities, transport systems, and industries, reduce wastes and residues, increase energy efficiency, and change our lifestyles. We also need new technologies to tackle climate change more rapidly, including carbon-dioxide removal technologies. If we take too long to achieve net-zero emissions in the coming decades, we will also require such technologies to remove carbon from the atmosphere to bring them back to pre-industrial levels. Otherwise, the global mean surface temperature will continue to be high, given that the cumulative emissions will remain high in the atmosphere for centuries and millennia, even after achieving a net zero.

Global Calculator – What is it, and what was your role in creating it? Is there more than one?
The Global Calculator is a system dynamics model aimed at simulating climate change mitigation pathways by 2050, including all sectors of the global economy. The objective is to inform policymakers, business leaders, and NGOs, but it is also a powerful learning tool for education. It has a simple web interface and is available in fully open access. The UK Government led the project, involving a multidisciplinary team from several institutions, including Imperial College London. I was one of its lead modelers.

We recently published a European Calculator too. Several nations have already developed their own 2050 Calculators, including Australia, Austria, Bangladesh, Belgium, Brazil, China, Colombia, Czech Republic, Ecuador, India, Indonesia, Ireland, Japan, Kenya, Mauritius, Mexico, New Zealand, Nigeria, South Africa, South Korea, Southeast Europe’s countries, Switzerland, Thailand, the United Kingdom, the United States, and Vietnam. I would encourage all those interested in climate change mitigation to explore them online.

You've worked and studied all over the world – Brazil, the UK, France, Japan, the United States … Do you think any particular country, region, or continent is taking the right approach?
Countries have different historical contexts, geographies, political aspects, infrastructures, and availability of natural resources. There is no one-size-fits-all approach, but important lessons can be shared. The calculators we have mentioned can help visualize and identify sustainable pathways for each nation. China, for example, has been a global leader in developing renewable energies and electric vehicles, but it remains very reliant on coal. At the same time, it is not easy to rapidly change the energy mix of a country with the largest population worldwide. Most investments in the energy sector take decades to be implemented and decommissioned. India, Pakistan, Bangladesh, and Indonesia, for example, also have high populations and significant development challenges, such as poverty reduction, education, housing, sanitation, health, and social inclusion. Therefore, comparing them with a few rich countries with a small population, good infrastructure, and political stability is unfair.

The right approach, so to speak, is associated with the capacity of national governments to translate their international commitments into effective policies domestically, for example, through innovative regulatory frameworks, carbon finance, certification schemes, private sector engagement, agroecological zonings, and environmental education. However, each country should find its own pathway according to its conditions and realities.

Does your home country, Brazil, face particular challenges in sustainability? If so, what are they, and how are they being addressed?
Yes, it does. Brazil has several sustainability changes, such as halting illegal deforestation and providing sanitation and waste treatment to its entire population, among other examples. Most of its greenhouse gas emissions are associated with deforestation and agriculture, including livestock, rather than the energy sector. Brazil has struggled to reduce its deforestation rates, particularly in the Amazon and Cerrado (a Savannah-like biome). This is a complex issue involving several vectors, such as illegal logging, land tenure, livestock expansion into critical areas, land-use opportunity costs, illegal mining, infrastructure development, criminality, and corruption, although the environmental law is already quite rigorous in the country.

At the same time, it is important to contextualize that about 58% of its territory is covered by forests, mainly native forests, whereas most nations are not even close to that. Brazil’s deforestation rates have increased in recent years, but the country significantly reduced them from 2004 to 2012. This shows that it is possible to achieve a net zero deforestation in the future, depending on the government’s efforts. Moreover, Brazil is one of the largest food producers and exporters, contributing to food security in several nations, including China. The country also has room to keep increasing crop yields, no-tillage systems, and agro-livestock-forestry integration, reducing the net greenhouse gas emissions related to food production.

In addition to agriculture, forestry, and other land uses, Brazil should continue to work on its energy transition. About 45% of the Brazilian primary energy mix is already comprised of renewable sources, including a successful biofuels program and a significant share of hydropower, wind power, bioelectricity, and solar energy. As a comparison, the world average is approximately 14%. Brazil’s renewable energy capacity has been increasing in the past decades. Still, its share in the total energy mix has been roughly the same because fossil fuel consumption has also increased. Therefore, the country should increase its renewable energy capacity more rapidly to achieve a net zero scenario by 2050 and simultaneously reduce its fossil fuel dependence and deforestation. By choosing this pathway, Brazil has the potential to become one of the largest markets for green investments globally.

The “carbon handprint” is the notion that organizations can (and should) not only try to reduce their own emissions, but also employ technology that lowers emissions for entire industries or cities. This is sometimes called carbon avoidance, or the enabling effect. How helpful do you think this will be in addressing climate change in the future?
Climate change is a collective and systemic problem. Heavy industries and converting companies are interconnected with several players, such as energy and feedstock suppliers, third services, and final customers. Cities also work as large networks involving residences, commerce, lighting, heating, transport, and other actors. Therefore, an organization should not only reduce its emissions but also work in harmony with a broader carbon mitigation strategy. Some sectors, for example, have emissions that are hard to eliminate, such as the cement industry, iron and steel, aviation, long-distance road transport, shipping, and load-following electricity, which is required to meet the growing share of intermittent renewables in the grid. Therefore, to achieve net zero, some negative emissions technologies will be necessary to offset such emissions. These technologies should not be used as an excuse to delay actions in reducing emissions. Both strategies, carbon reduction and removal, should be simultaneously addressed. We have no time to lose in tackling climate change.

Thus, concepts like carbon handprint, industrial ecology, circular economy, smart cities, and negative emission technologies are gaining momentum due to their importance in providing a systems approach to tackle complex problems. For example, from a systems perspective, if you buy an electric vehicle, but the electricity supplied to the grid is mostly from conventional coal power, the idea that your car is not emitting anything is just an illusion.

Anything else that you think is important?
Technology innovation is fundamental to help address the grand challenges of our time. However, technology alone is not sufficient. Every year, we have extrapolated our planetary boundaries due to overexploitation of natural resources, including fossil fuels, freshwater from aquifers, rocky fertilizers, such as phosphorus and potassium, and scarce elements, particularly lithium, copper, cobalt, and rare-earth metals. Therefore, as individuals, we are also part of the problem. We should reconsider our development patterns, social behaviors, and lifestyles, reconnecting ourselves to the environment, and using technology more wisely. This change includes, for example, reducing consumerism and selecting candidates more effectively committed to sustainability agendas in the elections. Nature can only heal itself if we stop damaging it and build more resilient systems, from local to global.