Comptes Rendus. Géoscience (Jan 2021)

Réchauffement climatique  : état des connaissances scientifiques, enjeux, risques et options d’action

  • Masson-Delmotte, Valérie

DOI
https://doi.org/10.5802/crgeos.29
Journal volume & issue
Vol. 352, no. 4-5
pp. 251 – 277

Abstract

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This article takes stock of climate change, based on three special IPCC reports published in 2018 and 2019. These reports provide integrated assessments across different scientific disciplines, and for the first time are written by scientists from different disciplines in each chapter. They provide an update on observed changes and their causes, future opportunities and risks, depending on the evolution of greenhouse gas emissions, socio-economic development choices, and shed light on solutions for climate action and for sustainable development, preserving biodiversity and enabling everyone to live in dignity.The first SR15 Special Report (October 2018) focuses on the impacts associated with a global warming of 1.5 °C, as well as compatible greenhouse gas emission trajectories, in the context of strengthening the response to climate change, sustainable development and efforts to eradicate poverty: www.ipcc.ch/report/SR15.The second SRCCL Special Report (August 2019) focuses on climate change and land use, particularly desertification and land degradation, sustainable land management, food security and greenhouse gas flows in terrestrial ecosystems: www.ipcc.ch/report/SRCCL. It addresses the challenges of both adaptation and mitigation.The third SROCC Special Report (September 2019) focuses on the ocean and cryosphere in an changing climate. It focuses on how climate change is affecting the ocean and the cryosphere, ecosystems and human societies, in high mountain areas, the regions polar, for the coastline, which is linked to the ocean, including via extreme and abrupt events. The mitigation options are not part of this assessment, except for “blue carbon” (the potential for carbon sinks linked to coastal marine ecosystems). This report highlights the challenges of action to building resilience: www.ipcc.ch/report/SROCC.This summary takes stock of the trends observed, their causes, the projections of future changes, in particular with regard to their impacts and risks, depending on the future greenhouse gas emission trajectories, and our collective choices.

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