Integrating climate and weather products in Water Resources Management by Francis Mutua University of Nairobi

Climate and Water Resources The climate of the Earth is controlled mainly by the energy from the sun Atmosphere Hydrosphere Lithosphere Biosphere Anthropogenic forces change the equilibrium

Climate variability Climate variability is strongly linked to variations in the the solar output – variability with time-scales > 1 yr. Examples: ENSO (3-6 yrs), sunspot activity ( 11 yrs), QBO ( 2 yrs), etc. The oscillation of the earth around the sun (Time-scale = seasons): Seasonality: notably in precipitation, temperature humidity and evaporation The combination yields seasons : BN NEAR- NORMAL ABN in precipitation Climate variability introduces a corresponding variability in the hydrological cycle

Climate Variability and Water Resources Hence climate variations have significant consequences on the quality and quantity of water in all hydrological regimes. Climate variability is the major cause of the extremes which are observed in hydrological systems: floods and droughts Thus floods (quick onset) and droughts (slow onset) hazards are part of the climate systems and therefore unavoidable However, they need not become disasters because it is possible to to be prepared for them (especially drought hazards) Often, they turn into disasters –Famine and crop failure –Deaths (humans and livestock) –Adverse economic impacts and impoverishment –Conflicts All because climate and weather information and products are not adequately factored into national disaster management.

Climate Change Climate change –The IPCC projections of air temperature change over the next century, following 2xCO 2 is an increase of 1 o to 3.5 o C, with a "best estimate" of 2 o C Ppt, Temp, winds, Press., Evp, etc. –The manifestation of climate change would imply that the water resources would respond with the corresponding irreversible trend (and perhaps higher variability) as with the climate. Other forcings which exacerbate the impacts of climate change on water resources –population pressure –land use and land management –agricultural and industrial developments –domestic attitudes –recreation demands, etc Ordinarily exacerbate water related disaster risks (floods+droughts) Now add climate change!

Scenarios for Assessing Impacts of climate change on Water Resources Uncertainties –Future emissions (SRES story-lines) –Future concentrations (climate CO 2 cycle chemistry physics) –Response of climate (Time lags) –Natural variability? –GCMs GCM/RCM Synthetic/Incremental Analoque Downscaling GCM Regional

Integrating climate-change in water resources management

Integrating Climate and weather in Water Resources Management