If Rocks Could Talk

Kim Cobb

School of Earth and

Atmospheric Sciences

• Pa

leocli

mate R

esearch • Georgia Tech •Cobb Lab

GoogleEarth

GoogleEarth

me

GoogleEarth

“Godzilla” El Niño event: a new record

meon1stcruise,Nov1997

November1997OceanTemperaturesNOAA

Is El Niño strengthening as part of anthropogenic climate change?

Corals are eye witnesses to climate change

over 100yrs

coral cores: time capsules of climate

Research Featured inEpisode 3: The Surge

over 500yrs

1250-1350AD

Coral1

8 O/1

6 Oratio

ElNiño(warm)

LaNiña(cool)

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015

−5.5

−5

−4.5

−4

b18O

IGOSS SST*Evans99−0.15*Nurhati09+0.03*X12−6+0.09X12−3+0.03X14−1+0.06*X14−14+0.12X14−7−0.033X14−9+0.00

SST

How accurate is the coralrecord of climate?

8coralgeochemistryrecordsvssea-surfacetemperature

Analyzing El Niño events in corals spanning the last 7,000yrs, we find evidence that El Niño may be strengthening in response to greenhouse gases.

Cobb et al,Science 2013

Analyzing El Niño events in corals spanning the last 7,000yrs, we find evidence that El Niño may be strengthening in response to greenhouse gases.

Climate models now project adoubling of “very strong” El Niño-type impacts by 2100.

(Cai et al., Nature Climate Change, 2015)

What about today’s coral reefs?

7 months of bleaching stress, and counting

ObservationsinNov,2015:90%bleachedupto30%dead 100%dead

coralcolonies

Whatwillwefindnextmonth?

Help usuncoverEarth’smysteries.

Choose EAS!

@coralsncaves

undergrads