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Climate and cryospheric changes within the Trans-African alpine zone: scientific advances and future prospects. Stefan Grab School of Geography, Archaeology & Environmental Studies University of the Witwatersrand, South Africa. Objectives:.

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slide1

Climate and cryospheric changes within the Trans-African alpine zone:

scientific advances and future prospects

Stefan Grab

School of Geography, Archaeology & Environmental Studies

University of the Witwatersrand, South Africa

slide2

Objectives:

  • To briefly review high altitude African mountain research
  • focusing on:
  • -climate
  • -cryosphere
  • - To identify potential research gaps
  • - To review recent initiatives aimed at developing African
  • Mountain research

S. Grab

slide3

Rationale – why focus on African mountain climates

‘observed changes in freezing-level height are related to a long-term

increase in sea surface temperatures in the tropics…..tropical

environments may be particularly sensitive because the changes in

tropical sea surface temperature and humidity may be largest and most

systematic at low latitudes’ (Diaz & Graham, 1996, Nature)

Significance of African Mountains (with re to climate)

-High tropical representation

-Extensive latitudinal representation

-Storehouses of climate change

-Refuge sites (human habitation, fauna & flora)

-Important water reservoirs in a drought prone continent

S. Grab

Climate change is impacting African mountain systems:

Cryosphere – hydrology – ecosystems – economies - vulnerabilities

slide4
What do we know?

Climate of Simen (detailed measurements during the late 1970’s by Hurni

Climate of Bale (detailed measurements/descriptions by Miehe & Miehe (1994); contemporary monitoring.

Contemporary macro-scale seasonal climate forecasting work (e.g. Gissila et al., 2004)

Long-term rainfall trends for highlands since ca. 1897 (highest station = 2750m)(Osman & Sauerborn, 2002)

Quaternary climate change - based on proxy records (e.g. pollen)

Ethiopian Highlands

Ras Dejen (4620m)

S. Grab

1:100000

Hurni & Messerli, 1980: Institute of Geography, Univ. of Berne

slide5

Ethiopian Highlands

  • What is required?
  • Archival based research for climate and cryogenic changes during historical times
  • Evidence for past permafrost = ?
  • Timing of deglaciation in different regions = ?
  • Installation of atmospheric and ground climate monitoring stations in high mountain regions (Simen, Bale etc)
  • Satellite based research (e.g. for monitoring contemporary snow & cloud cover)

Saneti Plateau – Bale Mnts S. Grab

Dejen Escarpment – Simen Mnts S. Grab

slide6

Mt Kenya

  • What do we know?
  • Early 1900 descriptive climate and glacier records.
  • Extensive work on sedimentary chronologies (moraine and lake sediments)(e.g. Mahaney 1970’s – 1980’s)
  • Radiocarbon-dated lacustrine sed. sequences & oxygen isotope records = high resolution chronology of glacial advances / moisture balances during the Holocene (e.g. Karlén et al, 1999; Baker et al., 2001).
  • Regular glacier surface area / mass balance reports since 1980’s (esp Hastenrath)
  • Glacier reviews (e.g. Mahaney, 1989; Hastenrath, 2005)
  • Periglacial phenomena documented (including rock glaciers)(e.g. Hastenrath, Grab)
slide7

Mt Kenya

  • What do we know….cont?
  • High mnt atmospheric and ground climate studies (Winiger 1981; Grab et al., 2004).
  • 1980’s onwards – CDE, Univ. Berne group agro climate & hydro studies - plateau region around Mt Kenya.
  • 1990’s onwards Global WMO/GAW station at 3678m (MeteoSwiss & Kenya Met. Dept) – for standard meteorological data, CO & O3 monitored since 2002.
slide8

Tyndal glacier (2004) Mountain Club of Kenya

In: Hastenrath, 2005

Tyndal glacier (1919) (Arthur, 1921)

slide9

World Glacier Monitoring Service (WGMS) has been published at 5 year intervals since 1959

Mt Kenya has had a 67% ice reduction between 1899-1993 (WGMS, 1998)

slide10

Global WMO/GAW station

Mt Kenya (3678m)

Mt Kenya

  • What is required?
  • Ensure continued climate monitoring at 3678m & 4200m. Reestablish the 4700m station near Point Lenana, adjacent to Lewis glacier.
  • Borehole temperature monitoring.
  • Detailed monitoring of Lewis glacier during its last phase of existence.
  • Constraints: Vandalism/theft

S. Grab

Global WMO/GAW station Mt Kenya (4200m)

S. Grab

slide11

Kilimanjaro

  • What do we know?
  • Early 1900 descriptive climate and glacier records.
  • Limited work on sedimentary chronologies (moraine)(e.g. Mahaney)
  • Very limited periglacial research (possibly 2 or 3 papers during 1970’s)
  • Regular glacier surface area / mass balance reports and reviews: from sketch maps, photos, tacheometry (late 1950’s) to aerial photogrammetry and Landsat Images (1980’s onwards) (e.g. Klute, Hastenrath, Osmaston, Kaser et al.)
  • Ice Core records and Holocene glacial chronology (Thompson et al.)
slide12

Kilimanjaro

  • What do we know…..cont?
  • 2000 onwards = continuous climate monitoring on northern Icefield (Hardy et al.)

Chan et al., 2007: Intraseasonal precipitation variability on Kilimanjaro and the East African region and its relationship to the large-scale circulation, Theor. Appl. Clim.

  • Recent & current research programmes on solar radiation modeling, ice-radiation geometry, volcanic interference, historical glacier cover change (Kaser et al.)
  • Volcanic activity (fumeroles/sulphur emissions) may have increased since late 1800’s.
slide13

Kaser et al. 2004

Source: http://www.geo.umass.edu/climate/tanzania/jan07.html

slide15

Kilimanjaro

Fumerole

  • What is required?
  • Ensure continued climate monitoring at the summit and at lower altitudes.
  • Establish presence, distribution & characteristics of permafrost.
  • Bore hole temperature recording to 2m depths for possible CALM site (Circumpolar Active Layer Monitoring)(proposal submitted by Palacios & Grab)
  • Record periglacial phenomena and processes
  • Monitoring geothermal activity (understanding geothermal heat sources)
  • Establishing multicentury ice cap histories (Kaser & team)

S. Grab

slide16

Ruwenzori – Virunga (Albertine system)

  • What do we know?
  • Ruwenzori – commentary on glaciers discussed occasionally

1950’s – Heinzelin

1950’s-1960’s – Whittow, Osmaston

1970’s- mid 1990 – apparent gap

1996 – review by Kaser & Noggler

post 2000 – ongoing + implications on hydrology

(Kaser team, Taylor team, Italian team, Eggermont team

  • Limited climate data:

Kabale (1867m)

Karisoke Research Centre (3100m): 1979 onwards

Sabinyo (Rurambo, 2500m) & Kinigi (2200m): data for limited years

Ruwenzori (current monitoring)

  • Historical documents (early 1900’s) describe environmental conditions.
  • Virunga – several early reports commenting on the snows of Karisimbi

‘It is…..nearly always snow-covered.’ (Jack, 1913)

‘….and the snow-capped crest of Karisimbi, ….’ (Philipps, 1923)

  • Virunga – no reports on glaciation/periglaciation

Alexandra (5109m)

Dave Van Smeerdijk

slide17

Ruwenzori – Virunga (Albertine system)

  • What is required?
  • Ruwenzori

– ongoing glacier work (Kaser, Italian groups, Eggermont et al.)

  • Establish periglacial phenomena and processes (permafrost?)
  • Establish CALM sites (if premafrost is present)
  • Establish additional atmospheric and ground climate monitoring at high altitudes ( Karisimbi & elsewhere?)
  • Establish status of previously installed weather stations.
  • Establish historical climate change in Ruwenzori (last 140 yrs – Taylor)

Dave Van Smeerdijk

slide18

Drakensberg – Maluti system

  • What do we know?
  • Substantial cryogenic (periglacial & glacial) research since the mid 1930’s (ca. 70 publications)
  • Several short term weather recording projects (Grab, Killick, Nel, Sumner etc)
  • Mountain climatology research from 1960’s onwards (Freiman, Grab, Nel, Tyson etc)
  • Current project on historical climate change (last 160 years) based on archival records (Nash, Grab)
  • Recent (2000 onwards) satellite and radar based climate studies (Snow distribution patterns, rainfall patterns etc) (Grab et al.)
  • Current project on snow mapping for risk assessment and disaster risk reduction (Grab, Linde)
slide19

Drakensberg – Maluti system

  • What is required?
  • High resolution / high precision palaeo-climate verification. Proposal to do cosmogenic dating and ostrachod work on recently (2007) discovered palaeo-lake sediments (Carr, Mills, Grab, Horne)
  • Establish permanent climate observatories.

S. Grab

Constraints: vandalism / theft

slide20

Establishing a Network of High Altitude Climate

Observatories in African Mountains - progress thus far:

The ‘Global Change Research Network in African Mountains’ (GCRN-AM)

was launched in July 2007, Kampala, Uganda:

MRI, Global Mountain Program, African Highland Initiative et al.

Established working groups:

Climate change

Land use / land cover change

Livelihoods / decision making

biological systems

slide21

Establishing a Network of High Altitude Climate

Observatories in African Mountains - progress thus far:

Planning workshop on establishing high altitude observatory

systems in Ethiopia, January 2008, Addis Ababa, Ethiopia:

Working group established (Grab, Zeleke et al.)

Possible observatory sites discussed

Concept proposal has been drafted

Next phase: comprehensive proposal to be written for potential funding.

slide22

Concluding remarks

  • Geophysical research outputs and current needs are highly
  • variable across the respective African mountain regions
  • Emerging requirements:
  • To develop a database for past geophysical research outputs and current programmes
  • To identify high priority monitoring regions
  • To establish regional monitoring networks:
  • - Installation of standardized weather stations, borehole probes
  • - Links with GCOS (Global Climate Observing System) and GTN-G (Global Terrestrial Network for Glaciers)