To avoid global warming by 2°C—mission impossible

Resumo

Investigations have been carried out into the basic implications of the decisions taken in December 2015 at the Paris conference of the countries–participants of the UN Framework Convention on Climate Change for the world energy and for the atmosphere and climate. Based on the studied historical record of specific CO₂ emissions in the energy production by different countries, it is shown that the implementation of the Paris Agreement will require an unprecedented effort to modernize the global energy sector; in particular, rapid elimination of coal from the global energy mix and a substantially increased share therein of carbon-free energy sources (hydro and nuclear power and alternative renewable energy sources (renewables)) to one third by the middle of this century. We have developed a scenario for the global energy demand mix corresponding to the guidelines of the Paris Agreement and its more conservative variant extending the trend of the last 15 years. It has been established that, under any of the development scenarios, the global mean temperature is to exceed the level of 1.5°C as soon as within a few decades. Using model simulations of the changes in the atmosphere and climate, we show that even the full implementation of the Paris Agreements will not prevent the increase in average global temperature by 2°C as compared to the preindustrial levels. The world community faces a difficult choice between the implementation of more stringent measures for reducing greenhouse gas emissions, which we believe to be almost unreal, and adaptation to utterly new climatic conditions, which will last for centuries to come.