Transcript El Viejo La Vieja

Monterey Bay Time Series
- El Niños during 92-93 and 97-98
- Transition from El Viejo to La Vieja
- The age of dinoflagellates?
Biological Consequences of
Climate Change
Francisco Chavez
Senior Scientist
MBARI
February 2007
An Introduction to Anomalies
The Length of the Record is Important
Behrenfeld et al., Nature 2007
Presentation also makes a difference
An unusual winter, is it Climate Change aka Global Warming
What is Climate Change?
• Depends on who you ask
• It is not only global warming, but any
change in climate, be it due to nature or
man, on any scale (e.g. interannual to
centennial or longer)
National Academies Report 2006
Little Ice Age
“The extended reconstructed sea surface
temperature (ERSST) was constructed using
the most recently available International
Comprehensive Ocean-Atmosphere Data Set
(ICOADS) SST data and improved statistical
methods that allow stable reconstruction
using sparse data. This monthly analysis
begins January 1854, but because of sparse
data the analyzed signal is heavily damped
before 1880. Afterwards the strength of the
signal is more consistent over time”
Unfortunately SST is our only long term instrumental
record in the ocean
Upwelling regions account for 1% of the ocean but ~50% of the global fish production
Climate Change and the Abundance of Small Pelagic Fish
Atmosphere and Climate
Ocean Thermal
Dynamics and
Circulation
Surface
Warming
Freshwater
fluxes
Precipitation,
wind, dust supply
Macronutrients
plus iron
Primary
Productivity
Habitat and
distribution
Recruitment
Mortality
and
Predation
Zooplankton
Small Pelagics
Fisheries
Strong Northern Hemisphere Bias in Recent Warming
– effects not uniformly distributed
Reynolds and Smith, 1981-2006
Let’s take out the trend and look at the residual variability – First EOF of global SST
Pacific
Decadal
Oscillation
(PDO)
All of these were
calculated
exactly the same
way as the PDO.
So ……
Should it be the Global Multi-decadal Oscillation?
Regime shift
It is a familiar story
El Niño
Child
La Niña
El Viejo
El Viejo
Parent
La Vieja
La Vieja
MBARI
time series
1900 to 2000
1984 to present
California has become
more productive!
Monterey
Primary
Production
Monterey
Chlorophyll
CalCOFI
Chlorophyll
The Sea Level Story
Monterey Bay
Temperature
at Depth
Temperature at
60 meters
Nitrate at
60 meters
Monterey Bay
Nitrate at Depth
Local Ocean ecosystem
responds to large scale forcing
Monterey Bay
Surface
Chlorophyll
1985
1990
1995
2000
2005
Monterey
SST
Monterey
Temperature
at Depth
Forcing from above?
Monterey
Dinoflagellates
A fly in the ointment?
• The prevailing thought is that when the
world warms ecosystems become less
productive
• The developing paradox of what happened
during the Little Ice Age
The northwest African margin is a
coastal upwelling system. Sea
surface temperature (SST) records
from Moroccan sediment cores,
extending back 2500 years, reveal
anomalous and unprecedented
cooling during the 20th century,
which is consistent with increased
upwelling. Upwelling-driven SSTs
vary out of phase with millennialscale changes in Northern
Hemisphere temperature
anomalies (NHTAs) and show
relatively warm conditions during the
Little Ice Age and relatively cool
conditions during the Medieval Warm
Period. These results suggest that
coastal upwelling may continue to
intensify as global warming and
atmospheric CO2 levels increase.
McGregor, Dima, Fischer, Mulitza Science, 2/2/2007
Fish Scale Record from a core off Peru – Surprise, the
anchovy and other fish disappear during the Little Ice Age
Little Ice Age
Paleopeces (unpub. data)
Warmer coastal upwelling and warmer world
El Niño
Same thing during El Viejo
A developing Paradox
• Observations from the modern record show that
the entire globe warms during El Niño and El
Viejo and in coastal upwelling systems (at least
in the Pacific) temperature goes up and
productivity goes down. The opposite seems to
happen during the Little Ice Age when the
coastal upwelling system off NW Africa warmed
and the coast of Peru became less productive.
We must be looking at very different
mechanisms ….
• Will there be more fish in a warmer world?