Volume 10 Issue 7, July 2020

The COVID-19 pandemic will be an unprecedented test of governments’ ability to manage compound risks, as climate hazards disrupt outbreak response around the world. Immediate steps can be taken to minimize climate-attributable loss of life, but climate adaptation also needs a long-term strategy for pandemic preparedness.

Expectations for the Task Force on Climate-related Financial Disclosure’s framework to drive climate action in the private sector are high, and there is growing interest in its relevance for guiding public sector climate action. However, consideration of the framework’s limitations is critical prior to public sector application.

Synergistically addressing local and global environmental damages rather than optimizing a specific aspect of the policy conundrum helps to effectively foster climate action in road transport while maintaining public acceptance and socially fair outcomes.

In risk analysis, it is recognized that hazards can often combine to worsen their joint impact, but impact data for a rail network show that hazards can also tend to be mutually exclusive at seasonal timescales. Ignoring this overestimates worst-case risk, so we therefore champion a broader view of risk from compound hazards.

Migrants arriving in cities must overcome many challenges, including gaining acceptance from established residents. New research from Kenya and Vietnam shows urbanites accept climate hazards as being as legitimate as economic, political or social motivations for rural-to-urban migration.

Pacific Islands are already responding to the adverse effects of climate change, but it is unclear to what extent these responses effectively and sustainably improve local resilience. New research seeks to understand how local beneficiaries evaluate adaptation projects and what this teaches us for future adaptation.

The Madden–Julian oscillation causes teleconnections that impact mid-latitudes. Now research predicts dramatic eastward shifts of these impacts in the Pacific–North America region as the climate warms, leading to higher winter rainfall variability along the US West Coast and California in particular.

Reference scenarios are used to evaluate different mitigation scenarios, allowing understanding of their relative strengths and weaknesses. This Perspective considers the appropriate use of reference scenarios in mitigation analysis across different policy contexts.

The impacts of extreme weather and climate can be amplified by physical interactions among events and across a complex set of societal factors. This Perspective discusses the concept and challenge of connected extreme events, exploring research approaches and decision-making strategies.

People may choose or be forced to relocate due to climate change. Here the authors show that urban residents in Vietnam and Kenya view climate conditions as a legitimate reason for migration from rural to urban areas, but environmental migrants are not seen as more deserving than economic migrants.

Community-based adaptation, in principle, leverages existing local knowledge, capabilities and priorities, but it is unclear what factors drive its success or lack thereof. Here the authors evaluate 32 community-based adaptation initiatives in the Pacific Islands and identify key optimization points for future initiatives.

Carbon dioxide removal (CDR) will be necessary to meet climate targets. Applying equity principles to allocate national CDR quotas shows a large variation across countries and principles, while within the EU domestic biophysical limits constrain individual capacity to achieve them.

COVID-19 pandemic lockdowns have altered global energy demands. Using government confinement policies and activity data, daily CO₂ emissions have decreased by ~17% to early April 2020 against 2019 levels; annual emissions could be down by 7% (4%) if normality returns by year end (mid-June).

The Madden–Julian oscillation (MJO) is a band of convection that travels eastward through the tropics and impacts mid-latitude weather via teleconnections. Under climate warming, these teleconnections are predicted to extend eastward in the Pacific–North America region, amplifying MJO impacts there.

The Barents Sea cools the ocean, and dense water masses form that flow into the global overturning circulation. Hydrographic observations from 1971 to 2018 show reduced cooling efficiency with warmer Atlantic inflow, reduced sea ice and reduced wind-driven heat loss.

The North Atlantic ocean warming hole has been linked to reduced tropical heat import. Model simulations show an anthropogenically forced increased heat export poleward from the region, by overturning and gyre circulation, and shortwave cloud feedback control the warming hole formation and growth.

Warming is predicted to weaken the Atlantic Meridional Overturning Circulation. Simulated temperature stabilization at Paris Agreement targets shows recovery to a level independent of the target, with continued North Atlantic warming and North Atlantic sea-level rise lower than the global mean.

Surface CO₂ concentrations in the western Arctic Ocean differ due to local processes. During the period 1994–2017, the Canada Basin has shown rapid increases as warming and ice loss enhance air–sea exchange of CO₂, whereas the Chukchi Shelf has strong biological activity, resulting in a CO₂ sink.

Methane emissions are determined by the balance of microbial methane production relative to consumption. Warming drives larger increases in methane production than consumption in experimental ponds, suggesting that natural ecosystems may represent a positive feedback under climate change.

Evapotranspiration links productivity with water cycling between land and atmosphere. A model including plant hydraulics better describes the response of evapotranspiration to stress from vapour pressure deficit and soil moisture under rising temperatures than approaches common in Earth system models.