Future projections of global-sea level rates from glacier models
Thursday, December 2 at 11:00AM (MDT): Dr. Lavanya Ashokkumar
Glaciers contribute significantly to mass loss and sea-level rates. Apart from anthropogenic causes, thermal and ocean warming are the major causes for glacier melt. Compared to glaciers worldwide, ice mass loss rates from Alaska and the Canadian Archipelago are highest and it is expected to increase through the end of the century in response to increasing temperatures. We developed a glacier model based on regional calibration from GRACE monthly observations for estimating the future evolution of mass loss from Alaska and Canadian Archipelago. The main purpose of using GRACE observations is to include the mass balance seasonality at monthly temporal intervals from all glaciers within a specific region in the model calibration. Our estimates of future sea level rates are based on the inclusion of GRACE mass balance (seasonality) for the observation period between 2002 and 2017, instead of calibrations from direct observations. The high temporal and regional spatial resolution of GRACE mass balance estimates allows us to estimate regional glacier sensitivities to atmospheric changes in temperature and precipitation, while accounting for glacier area and volume changes.
We find substantial mass loss from Alaska, Arctic Canada South, followed by Arctic Canada North. Alaska contributed -22 ± 6 mm of SLE under RCP 2.6 and -38 ± 11 under RCP 8.5, Arctic Canada North contributed -18 ± 8 mm under RCP 2.6 and -38 ± 12 under RCP 8.5, while Arctic Canada South contributed -12 ± 4 under RCP 2.6 and -21 ± 6 at RCP 8.5. The mass loss rates from our model were nearly consistent with other glacier models under the GlacierMIP2 initiative. The mass loss rates are slightly higher from CESM-LE. In case of volume loss, we find that Alaska (26% at RCP 2.6 and 46% at RCP 8.5) and Arctic Canada South (28% at RCP 2.6 and 40% at RCP 8.5) are the largest contributors to volume loss.
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