Maria Gabriela Meirelles, Speaker at Climate Change Conferences
University of the Azores, Portugal
Title : Climate change: The impact of rising temperatures on the reduction of global yield of the main cereal crops.


There are many ways in which climate change can impact food security and therefore human health. Our climate is changing and, given the levels of greenhouse gases already present in our atmosphere, these potentiate extreme weather events, with social, economic and ecological consequences. Increasingly higher global average temperatures are likely, if drastic changes in greenhouse gas emissions are not registered, through a wide range of policies to be adopted. Over the last half century, the direct impact of climate change has manifested itself in the decrease in crop yields of cereal crops (corn, wheat, rice and soybeans). According to the United Nations, currently, one in every nine people in the world is undernourished, making a total of 815 million of people. If no measures are taken, the forecast is that this number will reach two billion people in 2050. Soil protection and restoration are therefore important for food security, climate change mitigation and biodiversity conservation. This includes sustainable agriculture practices, such as the use of low-carbon agricultural practices and the recovery of degraded areas. Soil biodiversity and sustainable soil management are preconditions for attaining Sustainable Development Goals (SDGs). Food production through sustainable agriculture are preconditions for attain some of the Sustainable Development Goals (SDGs). These are: Goal 1 - No Poverty, Goal 2 - Zero Hunger, Goal 5 - Gender Equality, Goal 6 - Clean Water and Sanitation, Goal 10 - Reduced Inequalities, Goal 12 - Responsible Consumption and Production, Goal 14 - Life Below Water and Goal 15 - Life on Land.

In this study we use the En-Roads simulator, which is a simulation model that explores how to deal with global energy and climate challenges through political, technological and social changes. It lets you create scenarios that focus on how changes in taxes, subsidies, economic growth, energy efficiency, technological innovation, carbon prices, fuel mixes, and other factors will change global carbon emissions and temperature. Considering current data, the simulator predicts a temperature increase of 3.6°C by the year 2100. A concentration of greenhouse gases that will be around 907.86 ppm, with 712.6 ppm of CO2. The projected temperature increase has negative consequences on cereal production. Showing a 21% decrease in corn harvest yield, 17% for wheat, 9% for rice and soybeans.

Considering in 2100 a world population of around 11.8 billion people, a growth of the world economy around 2.5% per year and introducing public policies in terms of energy supply, transport, buildings and industry and of land use, the simulator predicts a warming of 1.5°C by 2100, using the pre-industrial era as a reference. For such a scenario to be feasible, the supply of energy will have to take place using renewable alternatives. To discourage the use of fossil fuels, the price of carbon in 2100 should be around 250 $/ton CO2. Taking 2021 as a reference, there must be a 50% reduction in the use of oil and 85% in the use of coal, while energy efficiency in transport should grow by 4.9%/year, so that by 2100 all vehicles were electric. In buildings and industry, energy efficiency must grow by 5%/year and electrification by 100%. Regarding greenhouse gas emissions from the soil, it is necessary to reduce deforestation by 10%/year and reduce CH4 emissions by 60%. In industry, it is the emission of fluorinated gases that will have to be reduced by 60% by the end of the century. This simulation also took into account the removal of existing carbon in the atmosphere through afforestation (planting 98% of the land reserved for this use) and the removal of 30% using technologies for this purpose. Against this backdrop, projections indicate a 6% decrease in corn harvest yields, 4% for wheat, 2% for rice and soybeans.

Food security is associated with global political strategies, including the United Nations SDGs and compliance with the Paris Agreement, contributing to a lower impact on cereal production.

Audience Take Away   

  • Understand how the Sustainable Development Goals can contribute to food security.
  • Through the simulation of scenarios using the En-Roads simulation model.
  • Participate in political, technological and social decisions about global challenges.
  • ???????Allow each citizen to rethink their lifestyle.         
  • ???????Yes, they can create scenarios and obtain future climate projections, using the En-Roads simulation model.
  • ???????This provide a practical solution to a problem that could simplify or make a designer’s job more efficient
  • It improve the accuracy of a design, or provide new information to assist in a design problem.


Maria Gabriela Meirelles has a Diploma in Physics from the State University of Rio de Janeiro, Brasil in 1992, a Geophysics Master in the field of Meteorology from University of Lisbon (Faculty of Sciences), Portugal in 1997 and got her PhD in Physics from the Azores University (UAC), Portugal in 2009, in the field of Geophysical Sciences. Her teaching activities include topics on meteorology/atmosphere/climatology, general physics, physics for biology and geophysics, among others, for under graduate and master studies. She has participated in several scientific conferences and she has published several research articles and book chapters.