The economic modeling tool GEMMES is one of the few to integrate the impact of climate change into country GDP and debt forecasts. Designed by the Agence Française de Développement, it is now available in an online application accessible to all.

Can you find a climate policy that will keep the rise in the Earth’s mean atmospheric temperature below +2°C while maintaining a prosperous economy? This is the challenge launched by "GEMMES", an economic modelling tool designed by the Agence Française de Développement (AFD) and now available in an online application accessible to all.

The result of two years of research, it is one of the first such tools to take into account both economic development and environmental sustainability. Keeping in mind that instability in one of these areas will inevitably have significant repercussions in the other.

GEMMES makes it possible to vary the values of different parameters related to the environment (temperature, carbon storage capacity in the biosphere, etc.) and the economy (labor productivity, debt-to-GDP ratio, carbon prices, etc.) to understand their influence on changes in GDP, debt or greenhouse gas emissions.

A reflection on the carbon price

The aim is to convince countries of the need to act on climate change, and above all to do so in the right way. The application thus focusses in particular on carbon pricing.

Is setting a high price for carbon effective? The answer is no: this will inevitably have serious consequences for the economy in the long term. On the other hand, if the price is too low, the measure will not have a very significant impact on the climate. What we are trying to show with GEMMES is that the carbon price cannot be used as the only instrument of an environmental policy” insists Antoine Godin, AFD economist-modeler and contact person for the GEMMES project.

Since projections vary from one country to another, AFD first developed different versions of Gemmes that were each adapted to a particular economy: Brazil (with a focus on the energy sector), Colombia (transition risks), Côte d'Ivoire (raw materials and the informal economy), Vietnam (impact of climate change on coastal areas), Tunisia and Morocco (impact of climate change on agriculture).

“A collapse is possible"

An application based on the general model was then put online - in French, English and Spanish. It is accessible in open source, meaning that everyone can reuse the source code. "It is important to be entirely open to gain credibility" says Antoine Godin.

Three modules - climate, economic and political - enable users to "play" with the data to visualize their impacts on the economy or greenhouse gas emissions. A world map also shows that the global increase in temperatures will not affect countries in the same way.

What will a rise in global mean temperature of +4°C mean at the local level?” We want to show that we must be prepared for unexpected consequences. And that a collapse of our societies is possible, both economically and environmentally,” warns Antoine Godin. We have thus been warned.

Discover GEMMES by clicking here


Further reading:

COP24: "We need more climate ambition"

Digital Africa, the digital ally of social and inclusive entrepreneurship

Fiji’s Resisters