Ten new insights in climate science 2021: a horizon scan

Non-technical summaryWe summarize some of the past year's most important findings within climate change-related research. New research has improved our understanding about the remaining options to achieve the Paris Agreement goals, through overcoming political barriers to carbon pricing, taking into account non-CO2 factors, a well-designed implementation of demand-side and nature-based solutions, resilience building of ecosystems and the recognition that climate change mitigation costs can be justified by benefits to the health of humans and nature alone. We consider new insights about what to expect if we fail to include a new dimension of fire extremes and the prospect of cascading climate tipping elements.Technical summaryA synthesis is made of 10 topics within climate research, where there have been significant advances since January 2020. The insights are based on input from an international open call with broad disciplinary scope. Findings include: (1) the options to still keep global warming below 1.5 °C;(2) the impact of non-CO2 factors in global warming;(3) a new dimension of fire extremes forced by climate change;(4) the increasing pressure on interconnected climate tipping elements;(5) the dimensions of climate justice;(6) political challenges impeding the effectiveness of carbon pricing;(7) demand-side solutions as vehicles of climate mitigation;(8) the potentials and caveats of nature-based solutions;(9) how building resilience of marine ecosystems is possible;and (10) that the costs of climate change mitigation policies can be more than justified by the benefits to the health of humans and nature.Social media summaryHow do we limit global warming to 1.5 °C and why is it crucial? See highlights of latest climate science.

Impact of COVID-19 on India: alternative scenarios for economic and social development

The COVID-19 pandemic has led to major learning about the social and economic losses that an external shock to the system can cause. In this paper, we examine some sustainability issues focusing on three key focal points of sustainable development – economic growth, poverty and inequality in the context of climate change. We focus on the inter-relationship between economic growth, investment, labour force participation, energy consumption, poverty and inequality under alternative scenarios using the global framing of Shared Socio-Economic Pathways (SSPs). An econometric model is used for estimating the relationship between GDP and its determinants along with fitting a General Quadratic and/or Beta Lorenz curve using the World Bank’s Povcal software for determining the relationship between income, poverty and inequality. Alternative GDP growth paths, redistribution assumptions and poverty lines are used for simulations which reveal the extent of sensitivity of the developmental targets to scenarios up to 2030.

Guidelines for Modeling and Reporting Health Effects of Climate Change Mitigation Actions.

BACKGROUND: Modeling suggests that climate change mitigation actions can have substantial human health benefits that accrue quickly and locally. Documenting the benefits can help drive more ambitious and health-protective climate change mitigation actions; however, documenting the adverse health effects can help to avoid them. Estimating the health effects of mitigation (HEM) actions can help policy makers prioritize investments based not only on mitigation potential but also on expected health benefits. To date, however, the wide range of incompatible approaches taken to developing and reporting HEM estimates has limited their comparability and usefulness to policymakers. OBJECTIVE: The objective of this effort was to generate guidance for modeling studies on scoping, estimating, and reporting population health effects from climate change mitigation actions. METHODS: An expert panel of HEM researchers was recruited to participate in developing guidance for conducting HEM studies. The primary literature and a synthesis of HEM studies were provided to the panel. Panel members then participated in a modified Delphi exercise to identify areas of consensus regarding HEM estimation. Finally, the panel met to review and discuss consensus findings, resolve remaining differences, and generate guidance regarding conducting HEM studies. RESULTS: The panel generated a checklist of recommendations regarding stakeholder engagement: HEM modeling, including model structure, scope and scale, demographics, time horizons, counterfactuals, health response functions, and metrics; parameterization and reporting; approaches to uncertainty and sensitivity analysis; accounting for policy uptake; and discounting. DISCUSSION: This checklist provides guidance for conducting and reporting HEM estimates to make them more comparable and useful for policymakers. Harmonization of HEM estimates has the potential to lead to advances in and improved synthesis of policy-relevant research that can inform evidence-based decision making and practice. https://doi.org/10.1289/EHP6745.

Reduced air pollution during COVID 19: Learnings for sustainability from Indian Cities

Air pollution has been a widespread and visible concern, that has increased significantly over the last decade across many parts of India with severe consequences for human health and well-being. The Indian government, as in many other countries, responded to the COVID 19 pandemic by enforcing a variety of restrictions on normal activity, including complete lockdowns that led to severe disruptions in economic activities. A beneficial short-term effect on the natural environment across cities was a significant reduction in air pollution. The pandemic and its management, have brought home the interconnectedness between nature and human existence with renewed understanding of the complex linkages between the economy and the environment. This presents a unique opportunity to integrate air pollution management into plans for economic recovery. This paper empirically examines the impact of imposing a 27-daylockdown on air pollution in India by comparing pollutant concentration data from 8representative cities over matching periods of time during the lockdown with those ofthe previous year, and the National Ambient Air Quality Standards (NAAQS). This provides an opportunity to understand the maximum extent to which air pollution could potentially be reduced in these cities. Thereafter, these findings are analysed in conjunction with city level socio-economic correlates and current air pollution management strategies, to gain policy insights on the scope for integrating improved air quality with economic recovery for a sustainable future. With city action plans having been recently prepared for improving air quality, this is indeed an appropriate time to conduct analyses to impact and bend the curve of air pollution substantially. Additionally, as winter approaches, there is a possibility of a double burden of mortality and morbidity from worsening of both Covid-19 and air quality. The current focus on public health provides an opportunity to concentrate on the management of airp ollution as a critical component of public health management.