Turn down the heat: Why a 4°C warmer world must be avoided
About the Course
Under current pledges and commitments, the world is likely to reach a 4°C degree warming by the end of the century and 2°C warming as early as 2040. This MOOC brings leading and renowned scientists to provide a synthesis of the most recent scientific evidence and provides an analysis of likely impacts and risks with a focus on developing countries. It chronicles already observed changes in the climate system and its impacts, through the increase in carbon dioxide emissions, corresponding temperature increases and melting of glaciers and sea ice, and changes in precipitation patterns. It also offers projections for the 21st century for droughts, heat waves, sea level rise, with implications on food and water security as well as possible impacts on agriculture, water availability, ecosystems and human health.
The MOOC presents this analysis for the likely impacts of a 4-degree warming trajectory and stresses the need for decision makers and communities to take a firm look at their adaptation choices, while signaling the urgency for mitigation action. Participants will also be introduced to the risks of triggering non-linearity, and tipping elements like the disintegration of the West Antarctic ice sheet and large-scale Amazon dieback. This MOOC ends with a discussion on the main policy choices needed to prevent warming to be above 2°C.
Course Syllabus
Overview
This overview presents the main findings of the course, providing a summary of the key impacts and challenges of a 4°C warmer world by the end of this century.
Module 1: Observed Climate Changes and Impacts: Hundreds of Thousands of Years to Now
This module outlines the historical observed changes in the climate system leading up to the present day and the impacts that can now be attributed to human-induced climate change. It examines the rise of GHG emissions since preindustrial times while explaining the link between CO2 concentrations and the rising global mean temperature, ocean heat storage and sea-level rise, as well as the uncertainties in the scientific evidence. It also describes the trends of increasing loss of ice in Greenland and Antarctica, increasing loss of Arctic Sea-ice, melting mountain glaciers, increased heat waves and extreme temperatures and finally, drought and aridity trends.
Module 2: Possible 21st Century Climates
This module provides an overview of the projected changes in climate leading up to the end of the 21st century. It describes the likelihood of a 4°C warmer world by 2100 A.D. and enables a deeper understanding of various climate models with different projections and key areas of uncertainty. It also reviews possible responses from natural systems, explaining how the projected changes in climate from 2°C to 4°C global warming could result in sea-level rise, heat waves and extreme temperatures, and ocean acidification.
Module 3: Life in a 4°C Warmer World
a) Impacts Across Key Human Support Systems
This module presents an overview of current and projected climate impacts across key human support systems such as agriculture and food production, water resources, ecosystems and biodiversity, and human health. Each of these human support systems will be negatively impacted by climate change under a 4°C global warming scenario, resulting in adverse consequences for development: diminishing crop yields which threaten food production and human health, loss of biodiversity, spread of vector-borne diseases and water scarcity.
b) Risks of Large-Scale and Disruptive Changes in the Climate System
This module brings together the information in the earlier modules, by considering how the impacts, risks, and vulnerabilities to climate change may scale with increasing levels of CO2 concentration and global mean warming. The module highlights the risks of nonlinear and cascading impacts and the risk of crossing critical thresholds for nonlinear tipping elements of the earth system, which could dramatically increase vulnerability to climate change and impose multiple stresses on development.
Module 4: What Can We Do About It: Choice is in your hands (Discussion)
After having outlined the scientific evidence in previous modules, this final module goes beyond the WB/PIK report and provides a discussion on what mitigation and adaptation action is needed to help avoid a 4 degree world while also decreasing the vulnerability of climate change impacts and building climate resilience. Since there is no single solution, this module will share perspectives from a range of actors on some of the key policy measures and climate actions. Track 1 (for the general public) will showcase how different lifestyles may affect changes in the climate and explore everyday choices that can help mitigate climate change and decrease vulnerability to impacts. Track 2 (for policymakers) invites leaders from various countries, the World Bank, IMF and civil society to exchange ideas and examples of effective policies and actions that can help transition towards a low emissions and climate resilient development path.
Course Format