NCIS 2019 Background

Background:

Climate change is impacting society and ecosystems and this is expected to worsen in the future. The IPCC Special Issue: Global Warming of 1.5°C identifies that ambitious mitigation and transition strategies to low-CO₂-producing energy sources are needed to prevent irreversible effects to the climate system. However, even using the most optimistic future projections within the WCRP CMIP6 scenarios, the proposed climate targets of 1.5°C or 2.0°C are unlikely to be reached with mitigation alone. The current trajectory suggests at least 3°C warming by the end of this century.

Different climate response strategies have been proposed, including Carbon Dioxide Removal, which includes the active removal of CO₂, reduced deforestation or afforestation, bioenergy with carbon capture and storage and other technologies; and Solar Radiation Management, the artificial increase of the reflectivity of the planet via dimming of the solar incoming radiation using reflective particles in the stratosphere or mirrors in space, brightening of clouds or thinning of cirrus, or making the Earth’s surface more reflective. Weather modification, interventions that attempt to impact local weather conditions, including rain/snow fall, potentially preventing local extreme weather events.

None of these approaches would likely be sufficient by themselves to counter the impacts of climate change. Furthermore, risks and benefits of these approaches depend upon each other. To tackle climate change and its impacts, we have to consider all options together in order to work toward a holistic solution. While each of these topics are traditionally separate research areas, more integration between them would lead to more coordinated research activities.

In addition to the physical science aspect, many questions have been raised about the governance and ethics of proposed technologies. These include concerns about who decides how to set the planetary thermostat, winners and losers, and slippery slope discussions regarding being unable to stop once started. International agreements on climate intervention applications or specific field experiments do not exist. Physical and social scientists need to collaborate in these arenas.

One important issue is how well we understand the physical climate and our confidence in models of this system to project future impacts and risks. Currently, there has not been sufficient effort to scientifically evaluate the predicted effectiveness of the various climate response strategies or their risks. With increasing climate impacts the need to appropriately inform public and policy on proposed climate intervention technologies is becoming more urgent.

NCAR / UCAR in collaboration with the scientific community is already involved in such efforts. However, much more could be done to increase confidence in modeling different approaches, through developing capacity to advancing models and obtaining required observations, and designing advanced future strategies and more realistic pathways. Increased exchange between different groups within NCAR / UCAR and the research community would enable more effective collaborations and communication of the findings.