ess w10 l1 - observed changes in cryosphere

cryosphere

Observing weather and climate:

In-situ measurements for glacier mass balance monitoring:

Current drivers of global warming:

Increased greenhouse gases caused by human emissions

Number of days with snow cover per year has declined over the last 5 decades:

Glaciers are melting worldwide:

Warming in the last 40-60 years has led to spring floods happening earlier by about 10 days per decade

Annual mass loss of glaciers is increasing:

Glaciers are losing hundreds of billions of tonnes of ice per year worldwide:

And loss of ice from glaciers is accelerating:

Greenland ice sheet:

•       Area ~ 2 x 10^6 km^2

• Approx. 1.2% of global land surface

• Contains enough ice to raise average sea level by 7.36m if all completely melted

Flows of ice in Greenland ice sheet:

•     Ice sheet velocity for 2007-2009 determined from satellite radar interferometry data

• Fastest flow in red, fast flow in blue and slower flow in green and yellow

Greenland ice sheet mass changes:

•        Ice loss in centimetres of water equivalent per year for

•    2003–2006 and 2006–2012

• Red: ice loss,  blue: ice gain

• From GRACE (Gravity Recovery and Climate Experiment) satellites: measure changes in Earth’s gravitational field, showing how mass is distributed around the planet

Changes in ice sheets: Greenland:

Antarctic ice sheet:

•     Area ~14  x 10⁶ km²)

• Approx. 8.3% of global land surface

•   Contains enough ice to raise global average sea level by 58.3m if all completely melted

Flows of ice in Antarctic ice sheet:

•   Ice sheet velocity for 2007–2009 determined from satellite radar interferometry data

•   Fastest flow in red, fast flow in blue, and slower flow in green and yellow

Antarctic ice sheet mass changes:

•   Ice loss from GRACE satellite measurements of Earth’s gravitational field changes

•   Centimetres of water equivalent per year for 2003–2006 and 2006–2012

•   Red: loss,  blue: gain

Changes in ice sheets: antarctica:

Comparison of ice loss from land ice bodies:

•     Antarctic Ice Sheet lost 2670 Gigatonnes of mass (uncertainty range 1800 to 3540) over 1992–2020

•     Greenland Ice Sheet lost 4890 Gigatonnes of mass (uncertainty range 4140 to 5640]) over 1992–2020

• Glaciers lost 6200 Gigatonnes of mass  (uncertainty range 4600 to 7800) over 1993–2019

Influences on recent sea level rise:

Permafrost changes:

   In the Northern Hemisphere, the southern limit of permafrost has been moving North since the 1970s

Permafrost changes: since 1980s

• Permafrost temperature increased by up to 2°C

•   Active layer thickness increased by up to 90 cm

Sea ice changes:

Arctic sea ice extent has declined since 1980, and become more variable

Averaged over 2010–2019, the monthly Arctic sea ice area from August to October was around 2 million km² (or about 25%) smaller than during 1979–1988

• Antarctic sea ice extent was steady or increasing until 2015, then declined:

•    Reproductive failures and declining abundances attributed to warmer polar oceans and less sea ice cover are observed in populations of polar bears, seals, whales and marine birds

 

River ice:

Betting on timing of when Tanana River ice will break up at