Increasing CO2 levels and temperature are intensifying the global hydrological cycle, with an overall net increase of rainfall, runoff and evapotranspiration, and will increasingly do so. The predictions of future rainfall regionally are fairly uncertain, there are, however, indications that the Mediterranean region will see reductions of rainfall and some equatorial regions, such as India and the Sahel, will see increases. The seasonality may also change, causing new, and sometimes unexpected, vulnerabilities.

The intensification of the hydrological cycle is likely to mean an increase in extremes – floods and droughts. There are suggestions that inter-annual variability will increase – with an intensification of the El Ninõ and NAO cycles – leading to more droughts and large-scale flooding events. These cycles are global phenomena which will impact different regions simultaneously (although often in different ways). Read more about the most important impacts of Climate Change will be on the Earth’s water cycle.

This Integrated Project Water and Global Change (WATCH) will bring together the hydrological, water resources and climate communities, to analyse, quantify and predict the components of the current and future global water cycles and related water resources states, evaluate their uncertainties and clarify the overall vulnerability of global water resources related to the main societal and economic sectors. WATCH project will:

  1. analyse and describe the current global water cycle, especially causal chains leading to observable changes in extremes (droughts and floods)
  2. evaluate how the global water cycle and its extremes respond to future drivers of global change (including greenhouse gas release and land cover change)
  3. evaluate feedbacks in the coupled system as they affect the global water cycle
  4. evaluate the uncertainties in the predictions of coupled climate-hydrological- land-use models using a combination of model ensembles and observations
  5. develop an enhanced (modelling) framework to assess the future vulnerability of water as a resource, and in relation to water/climate related vulnerabilities and risks of the major water related sectors, such as agriculture, nature and utilities (energy, industry and drinking water sector)
  6. provide comprehensive quantitative and qualitative assessments and predictions of the vulnerability of the water resources and water-/climate-related vulnerabilities and risks for the 21st century
  7. collaborate intensively with the key leading research groups on water cycle and water resources in USA and Japan
  8. collaborate intensively in dissemination of its scientific results with major research programmes worldwide  (WCRP, IGBP)
  9. collaborate intensively in dissemination of its practical and applied  results with major water resources and water management platforms and professional organisations worldwide (WWC, IWA) and at a scale of 5 selected river basins in Europe.