Himalayan glaciers lost 28% of ice in last 40 years

Change in ice loss in Himalayan glaciers — Ice thickness change (meters per year) at different elevations for 1975-2000 (blue) and 2000-2016 (red)

A new study of ice mass loss in 650 Himalayan glaciers over the past 40 years has revealed accelerating ice loss. The study recent extracted digital elevation models from declassified spy films which were compared with recent ASTER stereo imagery to quantify ice loss for the periods 1975–2000 and 2000–2016. The glaciers included in the study comprising approximately 34% of the total glacierized area in the region, or roughly 55% of the total glacial ice volume. The observed annual mass losses suggest that of the total ice mass present in 1975, about 87% remained in 2000 and 72% remained in 2016. The results also indicate that the average rate of ice loss was twice as rapid in 2000-2016 compared to 1975-2000.

Acceleration of ice loss across the Himalayas over the past 40 years, J. M. Maurer, J. M. Schaefer, S. Rupper and A. Corley, Science Advances 19 Jun 2019: Vol. 5, no. 6, eaav7266 DOI: 10.1126/sciadv.aav7266

From Our Files

Human beings as sensors provide raw data for scientific analyses

A recent study, published in Nature, reports on how anonymized data from three quarter of a million global smart phones was used to detect and map physical inactivity around the world. The study is an outstanding example of the type of scientific analyses that is possible using human beings as sensors.

Regional principal components for temperature and precipitation PNAS

Geospatial-temporal analysis reveals two trends in global climate during the last deglaciation

The last deglaciation was characterized by increases in surface temperatures of 10-15 °C punctuated by millennial-scale warming/cooling periods, pulses of increasing atmospheric carbon dioxide and asynchronously increasing methane. A geospatial-temporal variance analysis reveals a global warming trend correlating with rising CO2 on which is superimposed second trend millennial-scale regional warming/cooling periods associated with variation in the strength of the Atlantic overturning current.

Latest NASA research reveals several East Antarctica glaciers losing ice

In contrast to West Antarctica where several large glaciers have been losing ice for decades, East Antarctica glaciers have exhibited little evidence of ice loss but NASA’s latest detailed maps of East Antarctica ice velocity and elevation show that a number of glaciers have begun to lose ice over the past decade.

Southern Ocean warming preceded rising CO2 during the last deglaciation

Marine cores collected in the western tropical Pacific were used to compare the chronology of Southern Ocean warming near Antarctica and rising CO2 during the last deglaciation. The results provide evidence that the Southern Ocean off Antarctica warmed by ~2°C between 19,000 and 17,000 years before the present, about 1,000 years before the rise in atmospheric CO2.