Title : The Future We Need not impossible but difficult
Abstract:
The 20th century was fertile in the advancement of knowledge of the Earth System, in particular the atmosphere, and the simulation of its behavior through models. A climate model consists of a representation of complex and heterogeneous subsystems, with a large temporal scale, which are the constituents of the Climate System or Earth System. The results of the forecasts of several climate models indicates to an increase in the global average temperature of 3 to 4° for the year 2100, in relation to the pre-industrial values, considering the Scenario of Representative Trajectories of Concentrations RCP 6.0. En-ROADS is a simulation model that explores how to plan the global energy and climate challenges through political, technological, and societal changes. Allows to create scenarios that focus on how changes in taxes, subsidies, economic growth, energy efficiency, technological innovation, carbon pricing, fuel mix, and other factors will change global carbon emissions and temperature. For each simulation performed, the En-ROADS application calculates the results of ~14,000 equations, with a time interval of ~45 days, over 110 years, from 1990 to 2100, in 60 milliseconds. Considering current data on energy supply (coal, oil, natural gas, bioenergy, renewables, nuclear, new zero-carbon, carbon price), transport (energy efficiency, electrification), buildings and industry (energy efficiency, electrification), growth (population, economic growth), land and industry emissions (deforestation, methane and others) and carbon removal (afforestation, technological), the En-Roads simulator predicts a temperature rise of 3.6° around 2100. The Paris Agreement aims to achieve the decarbonisation of world economies and sets the objective of limiting the increase in global average temperature to 2°C by 2100, compared to pre-industrial levels, and continuing efforts to limit the temperature increase to 1.5°C, recognizing that this will significantly reduce the risks and impacts of climate change. Considering in 2100 a world population of around 11.8 billion people, a growth of the world economy of 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, taking the pre-industrial era as a reference. For such a scenario to be feasible, the energy supply will have to be made using renewable alternatives. To discourage the use of fossil fuels, the price of carbon in 2100 should be around 250$/ton CO2. Taking the year 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 should grow by 5%/year and electrification by 100%. Regarding greenhouse gas emissions from the ground, it is necessary to reduce deforestation by 10%/year and reduce CH4 emissions by 60%. In industry, the emission of fluorinated gases will have to be reduced by 60% by the end of the century. In this simulation, the removal of existing carbon in the atmosphere was also taken into account through afforestation (planting 98% of the land reserved for this use) and the removal of 30% using technologies for this purpose. This is one of several possible simulations, which show us a way to go in order to performed the Paris Agreement.
