Download Tales from East Africa"

”Tales from East Africa"
Tom Johnson
Large Lakes Observatory, and
Department of Geological Sciences
University of Minnesota Duluth
www.d.umn.edu/llo
Or, the title I suspect you may be thinking:
“Yet Another Professor’s Willy Nilly, Irresponsible
Expenditure of Federal Funds in Far-Away Lands”
The Great Lakes of East Africa
Turkana
Albert
Edward
Victoria
Tanganyika
Malawi
IPCC (IV) prediction of climate change during the 21st
century
(average of 21 climate models)
“Africa is one of the most vulnerable continents to climate
change and climate variability, a situation aggravated by
--- low adaptive capacity.”
Intergovernmental Panel on Climate Change, AR4, 2007
Looking for patterns and connections in the global climate system ----
What role (if any) has climate played in the evolution
of our species?
Cave paintings from
the Sahara
Tree rings
The “Paleoclimatologists”
Ocean drilling
Ice cores
Piston coring
On the ocean
On Lake Victoria
Finding the right place to core with seismic reflection profiling
Lake Tanganyika - 1982
R/V Nyanja – 36 ft, 12 tons
Our second night out on Tanganyika ----
Adrift and out of fuel
A tow into the village of
Nyanza Lac, Burundi
More than 4 km of sediment underlie the major rift lakes
Lake Tanganyika
Lake Turkana,
Kenya - 1984
Looking at Lake Turkana, Kenya to determine the Nile’s past
Blue Nile
White
Nile
Omo R.
Lake Turkana
Fossil diatoms indicate that an abrupt shift from freshwater to
saltwater conditions happened 4300 years ago
Dry
Wet
John Halfman, Ph.D thesis, Duke Univ.
The Old Kingdom of Egypt collapsed 4200 years ago
Exciting new developments ------
TEX86 – A proxy for past temperature
based on tetraether compounds (GDGTs)
from Thaumarchaea
marine Thaumarchaea(<1 mm)
bacteria
Hydrophilic head
Hydrophilic head
groups
groups
Hydrophobic
interior
Images courtesy of Johan Weijers
Lake Malawi
 >700m deep
 4th deepest lake
in the world
 ~600km long
and average of
55km wide
 Anoxic below
200m
A 25,000 year history of temperature in the African tropics
Recent warming
5000 years ago – a
surprisingly warm time in the
southern African tropics
Significant cooling during
the ACR and YD
Site 2
The last glacial maximum
Powers et al., 2005
Temperature records from Lake Tanganyika
show recent warming, much like the whole world
Site 2
Site 1
Diatom silty clay
Laminated
Nonlaminated
Calcareous silty clay - usually
bioturbated
A 1.2 million year record of temperature in the Malawi basin
EXISTING UNDERSTANDING
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Hominin evolution extends back some 7 million years
We have only begun to recover the record of human evolution!
African Great Lakes in Peril:
Lake Malawi example
Lake Malawi has ~1000 species of
fish: the most of any lake in the
world.
99% of these species are endemic to
the lake.
Ornamental fish trade serves as an
important source of foreign
exchange.
Fish provide 75% of the animal
protein intake for the people of
Malawi.
IPCC (IV) prediction of climate change during the 21st
century
(average of 21 climate models)
--------
5000 m3 water/ha y required for
irrigation. If applied to one million
hectares, amounts to 5 km3 water
per year.
"Promoting Irrigated
Agriculture in Malawi"
Lake Malawi level from ~1863 to 2011
Shire outflow
- 15 km3/y
- 10 km3/y
No outflow
from 1900 to
1935
- 5 km3/y
Outflow would stop!
Approximately 95% of Malawi’s electricity is derived from four
hydroelectric dams on the Shire River, which flows out of
Lake Malawi
Lake Malawi – the next Aral Sea?
Needs at the systems level approach
CLIMATE SYSTEM &
DYNAMICS
LAKE MALAWI DYNAMICS
HYDROLOGICAL ANALYSIS
HUMAN DIMENSION
LAND COVER/
LAND USE
The Research Team Co-PIs
• Climate - Sharon Nicholson, Florida State Univ.; Bette Otto-Bliesner, NCAR
• Hydrology - Assefa Melesse, Florida Intl. Univ.; Eric Wood*, Princeton Univ.
• Lake Dynamics - Jay Austin, Stephanie Guildford, Robert Hecky, Thomas Johnson,
Joe Werne*, all at Univ. Minnesota Duluth
• Human Dimension – Asli Aslan, Tracy Dobson, Anne Ferguson, Craig Harris, Sieg
Snapp*, Leo Zulu, all at Michigan State Univ.
• Ecosystem Services, Economic Tradeoffs – Stephen Polasky*, Univ. Minnesota
Twin Cities
Proposal in Review at NSF ---
Unique complexities of the system:
•
Data poor, underfed region of our planet
•
•
•
Poverty is prevalent
People are particularly vulnerable to the
whims of climate
Expatriate pressure for agriculture
development
Subsurface moorings in Lake Malawi
January 2012
My sincere thanks to my friends, colleagues and students in
UMD’s Large Lakes Observatory and collaborating
institutions
Funding provided over the years by:
• The U.S. National Science Foundation
• The U.S. National Oceanic and Atmospheric Administration
• The University of Minnesota
• The Petroleum Research Fund of the American Chemical Society
My sincere gratitude is extended to the Outstanding
Administrators who have ably laundered managed the
research grants in LLO over the past 17+ years:
• Mary Plante
• Colleen Denny
• Yvonne Chan
• Lori Johnson
And to the patient and highly professional members of
the UMD SPA team who have insured that our funny
papers preposterous propositions proposals always are
properly contrived formatted and arrive on time at the
funding agencies:
• Jim Loukes
• Elizabeth Rumsey
• Janice Sakry
• Bill Flaherty
• Claudia Carranza