REPORT: Climate Change 2021 The Physical Science Basis

9 August 2021. The most recent Intergovernmental Panel on Climate Change (IPCC) Report underlies the urgency of taking global action to halt climate change and deal with its unstoppable effects. The report, warns that without immediate, rapid and large-scale reductions in greenhouse gas emissions, it will be impossible to limit warming close to 1.5°C or even 2°C. 

Established by the United Nations Framework Convention on Climate Change (UNFCCC) in 2010, the Green Climate Fund (GCF) is mandated to help the world avoid the dangerous trajectory highlighted by the IPCC Report by financing climate action in developing countries. GCF bases its activities as the world’s largest dedicated climate fund on the latest scientific evidence.

The IPCC AR6 Summary for Policymakers provides the strongest evidence yet that human activities are causing climate change and making extreme weather events more frequent and more severe in every part of the world.

Resources:

IPCC (2021) Climate Change 2021The Physical Science Basis

The Working Group I contribution to the Sixth Assessment Report addresses the most up-to-date physical understanding of the climate system and climate change, bringing together the latest advances in climate science, and combining multiple lines of evidence from paleoclimate, observations, process understanding, and global and regional climate simulations.

• SUMMARY FOR POLICYMAKERS (SPM)
• TECHNICAL SUMMARY (TS)
• FULL REPORT
• INTERACTIVE ATLAS
• FREQUENTLY ASKED QUESTIONS (FAQs)
• REGIONAL FACT SHEETSDATA ACCESS
• OUTREACH MATERIALS

Extracts:

A stronger than global-average warming over land, combined with changing precipitation patterns, and/or increased aridity in some regions (like the Mediterranean) can severely affect land ecosystems and species distributions, the terrestrial carbon cycle and food production systems. (page 215)

Together with less oxygen in upper ocean waters and increasingly widespread oxygen minimum zones and in addition to ocean warming, this poses adaptation challenges for coastal and marine ecosystems and their services, including seafood supply.  (page 216)

Understanding water cycle changes over land, including seasonality, variability and extremes, and their uncertainties, is important to estimate a broad range of climate impacts and adaptation, including food production, water supply and ecosystem functioning. (page 219)

The rolling work programme of IPBES up to 2030 will address interlinkages among biodiversity, water, food and health. This assessment will use a nexus approach to examine interlinkages between biodiversity and the above-mentioned issues, including climate change mitigation and adaptation. Furthermore, IPBES and IPCC will directly collaborate on biodiversity and climate change under the rolling work programme. (page 222)

These large gross fluxes show the relevance of land management such as harvesting or rotational agriculture and the large potential to reduce emissions by halting deforestation and degradation.  (page 1173)

In the agriculture and waste sectors, livestock production has the largest emission source dominated by enteric fermentation by about 90%. Methane is formed during the storage of manure, when anoxic conditions are developed (page 1188)

According to the Special Report on Climate Change and Land assessment, agriculture, forestry and other land use (AFOLU) is a significant net source of GHG emissions (high confidence), with more than half of these emissions attributed to non-CO2 GHGs from agriculture. (...) For present day emissions, agriculture is the 2nd largest contributor to warming on short time scales (...) Aerosols produced from agricultural emissions, released after nitrogen fertilizer application and from animal husbandry, influence surface air quality and make an important contribution to surface particulate matter in many densely populated areas. (page 1488)

Pressures on this ‘food-energy-water nexus’ are further compounded by increasing globalization, which can transfer large-scale water demands to other regions of the world, raising serious concerns about local food and water security in regions that are highly dependent on agricultural exports or imports. (...) Changes in the quantity and seasonality of water due to climate change have long been recognized by IPCC and global development  agencies as heavily influencing the food security and economic prosperity of many countries, particularly in the arid and semi-arid areas of the world including Asia, Africa, Australia, Latin America, the Mediterranean, and small island developing states (page 1880)

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