Global Warming
•What is it?
•What’s causing it?
Lake Powell, Colorado River
CO2: one of themain heat-trapping gases.Its concentrationin theatmosphere,past 250 yrs.Past 10,000 yrs
It’sgettingwarmer
Hottest years:
2014
2010
2005
1998
Hottest decade:2001-2010
IPCC
NASA
Glacier nat park, Montanna-1
Glacier Nat Park,
Montana:
melting
1850: 150 namedglaciers.
2007: 26.
2030: 0 expected
Alaska: melting
Austria: melting
HIMALAYAS: MELTING.Mt. Everes (left), 1921 and 2007
Arctic: melting.1979 and 2003
Expected to be ice-free in summer by2030.
Reflectivity feedbackcould have seriousconsequences forGreenland.
Greenland surfacemelt extent.
Complete melting: 24 ft
sea-level rise.
The West Antarctic
ice sheet is melting
Would raise sea
levels 16 feet
Would take a few
centuries
May be already
unstoppable
• To see what this means, let’s turn to the past.
• 800,000 years of climate history.
• The “Pleistocene”: 2.5 Mya – today.
• CO2 was ~180 to 300 ppm.
present
interglacial
Temperature (red)
CO2 (blue)
Temperature (red)
CO2 (blue)
Today’s CO2 concentration: above 400 ppm!
To see what 400 ppm means …
… we must go back before theice ages (2.5 Mya to today):
• Pliocene era, 5 Mya - 2.5 Mya.
•Poles much warmer, tropics slightly warmer.
•Temperatures were 6 deg F warmer.
•Sea levels 70 feet higher.
The last time CO2 concentration
was ~ 400 ppm:
Will the CO2 spikebe the icon of a newgeological age?
Many geologistshave already namedit:
The Anthropocene
Is this what you wantfor yourgrandchildren?It’s a moral issue.
THANK
YOU!
We’re all in this together!
Thank you
