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 ChavezSenior Scientist

MBARIFebruary 2007

An Introduction to Anomalies

Behrenfeld et al., Nature 2007

The Length of the Record is Important

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

Small Pelagics

Fisheries

Ocean Thermal Dynamics and

Circulation

Atmosphere and Climate

Macronutrients plus iron

Zooplankton

Primary Productivity

Freshwater fluxes

Surface Warming

Precipitation, wind, dust supply

Recruitment

Mortalityand

Predation

Habitat and distribution

Climate Change and the Abundance of Small Pelagic Fish

Reynolds and Smith, 1981-2006

Strong Northern Hemisphere Bias in Recent Warming – effects not uniformly distributed

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

El Viejo La Vieja

El Viejo

La Vieja

MBARItime series

ChildEl Niño La Niña

Parent

1900 to 2000

It is a familiar story

MontereyPrimaryProduction

MontereyChlorophyll

CalCOFIChlorophyll

1984 to presentCalifornia has becomemore productive!

The Sea Level Story

Monterey BayTemperature at Depth

Monterey BaySurface Chlorophyll

Monterey BayNitrate at Depth

Local Ocean ecosystem responds to large scale forcing

Temperature at60 meters

Nitrate at60 meters

1985 1990 1995 2000 2005

MontereySST

MontereyDinoflagellates

MontereyTemperature at Depth

Forcing from above?

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 millennial-scale changes in Northern Hemisphere temperatureanomalies (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

Paleopeces (unpub. data)

Fish Scale Record from a core off Peru – Surprise, the anchovy and other fish disappear during the Little Ice Age

Little Ice Age

El Niño

Same thing during El Viejo

Warmer coastal upwelling and warmer world

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?