Prof Bill McGuire gave a highly interesting presentation at IHRR about the climate forcing of geohazards such as earthquakes and volcanoes. This has been a controversial topic, but is relevant for understanding how anthropogenic climate change influences Earth systems beyond the weather.
Prof McGuire is a contributing author of a chapter in a recent report from the Intergovernmental Panel on Climate Change (IPCC) (Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation) on the impacts of climate change on the physical environment. More relevant information on this important scientific issue reaching people working in policy throughout the world is currently needed, not to mention communities most affected by geohazards.
McGuire’s work is also relevant to research in ‘tipping points‘ in physical systems, including climate. It will be interesting to see what further research on the links between geohazards and climate reveals, how it is communicated in the future and whether it will be decisive in helping to build a strong enough political force to help reduce global CO² emission levels and encourage countries to adopt measures for climate adaptation. While the correlations between geohazards and climate change in some cases seems opaque, especially since the response of Earth systems to anthropogenic climate change may lag behind significantly, what researchers have learned from past climate change impacts will likely be helpful for understanding future extreme hazard events. Here are a few of the known effects of climate change on geosystems from the report that can lead to hazards:
- Changes in heat waves, glacial retreat and melting of permafrost affects mountainous areas, making slopes unstable and increased precipitation can lead to more landslides.
- Intense tropical rainfall induced collapses of the Soufriere Hills lava dome on Montserrat in the Caribbean.
- Large reduction in glacier cover in southern Alaska may have increased seismicity in the region where earthquake faults are close to failure.
- Large scale loss of ice mass in glaciated volcanic terrains reduces the load on the Earth’s crust and uppermost mantle causing magma to form and allows it to reach the surface more easily. ‘At the end of the last glaciations, this mechanism caused a more than 10-fold increase in the frequency of volcanic eruptions in Iceland’. But this effect is not confined to Iceland alone (see 23.37 of McGuire’s presentation above).
- As ice mass loss on glaciated volcanoes continues, Iceland, Alaska Kamchatka, the Cascade Range in the northwest United States, and the Andes could see more frequent eruptions ‘either as a consequence of reduced load pressures on magma chambers or through increased magma-water interaction’.
Video introducing the IPCC’s report: