Transcript Slide 1
WAKING THE GIANT: how a changing climate triggers earthquakes, tsunamis and volcanoes Bill McGuire Professor of Geophysical & Climate Hazards UCL UGLY SCIENTISTS….. José Mourinho. Chelsea FC Manager BBC Online. February 20th 2005 …..AND MAD ONES Plenty of evidence from the past Tiny changes in environment capable of triggering hazardous geological phenomena Climate change is already starting to affect the solid Earth Modelling suggests more to come PROXIMATE VERSUS ULTIMATE CAUSE A changing climate CAN NOT cause earthquakes, volcanic eruptions or landslides that would not have happened anyway Climate change has potential to act as a trigger or proximate cause Bring forward occurrence of a quake or eruption Potential influencer or modulator rather than ultimate cause The power of the ‘pressure of a handshake’ FINDING OUT MORE THE TALK 1. Looking back 3. Looking ahead 2. Where are we now? 4. The last straw ICEHOUSE TO GREENHOUSE IT’S ALL ABOUT WATER Temperatures up 6°C or so Cold, arid climate replaced by warmer, wetter, conditions 52 million cubic kilometres of water shifted from ice sheets into ocean basins 2 -3km thick ice sheets melted at high latitudes 130m load added to ocean basins Mass change lengthened day by 4 seconds WHAT GOES DOWN MUST COME UP Active fault Depressed crust Rising magma BOUNCING BACK Going up Going down EARTHSHOCK! Basel 1356 Stuoragurra Fault New Madrid 1811-12 Pärvie Fault TSUNAMI UK The great Storegga landslide VOLCANO STORM 52 million cubic km of water Continental ice sheets Ocean basins WATER…WATER! Action zone GLOBAL RESPONSE High Andes (Chile) Massif Central (France) Vesuvius San Andreas (California) WHERE ARE WE NOW? Kolka (Russia) 2002 Bagley Ice Field Bering glacier Mount Steller A CLIMATE TRIGGER FOR THE NEPAL QUAKES? NEWSWEEK cover story Climate change did not cause the Nepal quake BUT…… Recent research finds monsoon water loading in Gangetic Plain modulates earthquake occurrence in Himalayas Results in significantly more earthquakes Dec Feb GOING FORWARD Will we see a rise in numbers of quakes, eruptions and landslides worldwide? Will we be able to allocate a particular geological event to climate change? Are there places where we may see an unequivocal geological response to climate change? Are we able to identify especially susceptible seismic and volcanic threats? WAKING GIANT? Iceland uplift Vatnajökull Ice Cap Öraefajökull Bardabunga ICELAND REJUVENATED FURTHER AFIELD Etna Rainier Coastal volcanoes Snow-capped volcanoes Sollipulli Casita Tropical volcanoes A SHAKIER FUTURE? MEGAFLOOD More of this? Haiti 2010 Less of this? Japan 2011 Imja Tsho Nepal THE LAST STRAW Pavlof: sea level Taiwan tremors: typhoons Montserrat eruptions: rainfall Japanese earthquakes: snow NICE DAY FOR AN ERUPTION More eruptions occur from November to March Attributed to seasonal redistributions of water mass To conclude….. The climate and the solid Earth are intimately connected Role for CC in promoting hazardous geological events is well established ACC already triggering earthquakes and landslides in some regions Modelling suggests future response will be more widespread Most at risk are ‘critically poised’ systems Geologically ‘quiet’ regions may become active Seismic rejuvenation of Greenland Other regions will become more active Increase in major landslides in high-mountain terrain Jury out on whether there will be a discernible/statistically significance rise in the number of earthquakes, eruptions and landslides