Completed

April 2017– December 2018

Assessing the differences in climate impacts between 1.5°C and 2°C

Contacts

Dr Carl-Friedrich Schleussner

Funder

Bundesministerium für Bildung und Forschung

Partners

Goethe-Universität Frankfurt, Helmholtz-Zentrum Geesthacht, Max-Planck-Institut für Meteorologie, Hamburg, Deutsches Klimarechenzentrum GmbH

The HAPPI-DE project coordinates the German contributions to the Half a degree Additional warming, Prognosis and Projected Impacts initiative (HAPPI). HAPPI is a collaboration of 44 scientific institutions to generate new scenarios to quantify the relative risks associated with 1.5°C and 2°C of warming focusing on extreme weather and the relative risks of low-probability extreme weather events.

Climate Analytics is coordinating the consortium that will contribute global and regional climate model simulations to the HAPPI, as well as impact model simulations in the agriculture and water sector. The project’s main aim is to produce scientific publications in time for the Intergovernmental Panel on Climate Change's special report on 1.5°C in 2018.

Updates

Climate impacts at 1.5°C and 2°C – Results of the HAPPI DE Project Klimafolgen bei 1,5°C und 2°C

Climate impacts at 1.5°C and 2°C - Results of the HAPPI DE Project Klimafolgen bei 1,5°C und 2°C. The "HAPPI-DE" project has contributed to the efforts by the scientific community to provide targeted scientific input into the IPCC 1.5°C special report. Under the HAPPI-DE project, global and regional climate model simulations, as well as impact model simulations in the agriculture and water sector have been assessed resulting in 11 scientific publications.

Half a degree additional warming, prognosis and projected impacts (HAPPI): background and experimental design

Here, we document the design of the half a degree additional warming, projections, prognosis and impacts (HAPPI) experiment. HAPPI provides a framework for the generation of climate data describing how the climate, and in particular extreme weather, might differ from the present day in worlds that are 1.5 and 2.0 °C warmer than pre-industrial conditions.

Climate extremes, land–climate feedbacks and land-use forcing at 1.5°C

This article investigates projected changes in temperature and water cycle extremes at 1.5°C of global warming, and highlights the role of land processes and land-use changes (LUCs) for these projections. It is is part of the theme issue ‘The Paris Agreement: understanding the physical and social challenges for a warming world of 1.5°C above pre-industrial levels'.

Coordinating AgMIP data and models across global and regional scales for 1.5°C and 2°C assessments

The Agricultural Model Intercomparison and Improvement Project (AgMIP) has developed novel methods for Coordinated Global and Regional Assessments (CGRA) of agriculture and food security in a changing world. The present study aims to perform a proof of concept of the CGRA to demonstrate advantages and challenges of the proposed framework.

Risks for the global freshwater system at 1.5 °C and 2 °C global warming

To support implementation of the Paris Agreement, the new HAPPI ensemble of 20 bias-corrected simulations of four climate models was used to drive two global hydrological models in worlds approximately 1.5 °C and 2 °C warmer than pre-industrial.

Feasibility of limiting warming to 1.5 and 2°C

This briefing note outlines the scientific conditions under which warming can be limited to well below 2°C over the 21st century, and return to below 1.5°C by 2100.

Robust changes in tropical rainy season length at 1.5°C and 2°C

This article presents projections for changes in tropical rainy season lengths for levels of global mean temperature increase of 1.5°C and 2°C above pre-industrial levels.

Trajectories to a ‘1.5 °C warmer world’ may result in vastly different outcomes at regional scales

The many possible climates from the Paris Agreement’s aim of 1.5 °C warming

This Perspective in the journal Nature shows that trajectories towards a ‘1.5 °C warmer world’ may result in vastly different outcomes at regional scales, owing to variations in the pace and location of climate change and their interactions with society’s mitigation, adaptation and vulnerabilities to climate change.

Science aspects of the 2°C and 1.5°C global goals in the Cancun Agreements

This paper reviews the scientific literature on impacts for 1.5 and 2°C warming levels with focus on risks for Least Developed Countries. We summarise observed impacts in LDCs that have been related to global mean temperature and provide an overview of projected future changes.

Long-term sea-level rise implied by 1.5 degree and 2 degree Celsius warming levels

Sea-level rise is a critical and uncertain climate change risk, involving timescales of centuries.

Differential climate impacts for policy-relevant limits to global warming: the case of 1.5°C and 2°C

This article is a first comprehensive assessment of key climate impacts for the policy relevant warming levels of 1.5°C and 2°C above pre-industrial levels.

Impacts of 1.5 versus 2°C on cereal yields in the West African Sudan Savanna

This study considers the impact on crop yields and yield variability in regions currently challenged by food insecurity in the West African Sudan Savanna.

Soy field located in a rural area in the State of Paraná, Brazil.

Crop productivity changes in 1.5° C and 2° C worlds under climate sensitivity uncertainty

This article investigates the sensitivity of future crop yield projections with a set of global gridded crop models for four major staple crops at 1.5 °C and 2 °C warming above pre-industrial levels, as well as at different CO2 levels determined by similar probabilities to lead to 1.5 °C and 2 °C.

Freshwater stress on small island developing states: population projections and aridity changes at 1.5 and 2°C

This article presents projections of future changes in aridity on small islands and evaluates overall changes in freshwater stress in small island developing states at warming levels of 1.5 and 2°C above pre-industrial level.

Briefing note on the assessment “Differential climate impacts for policy-relevant limits to global warming: the case of 1.5°C and 2°C”

A new study analyses the differences in impacts the world would face at 1.5°C and 2°C in a comprehensive and comparable way for the first time. It finds that the increases in impacts between 1.5°C and 2°C are large, significant and pronounced for regions with limited adaptive capacity and high exposure.

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Decarbonisation targets and 1.5℃ pathways

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