1. Global Freshwater use

2. Freshwater Required for our sustenance. Used for drinking, industries, agriculture etc. 2.5% of total water on earth is freshwater. For human usage 1% only

3. Blue water Fresh surface and groundwater, in other words, the water in freshwater lakes, rivers and aquifers Green water The precipitation on land that does not run off or recharge the groundwater but is stored in the soil or temporarily stays on top of the soil or vegetation.

4. An estimated 25% of the world’s river basins run dry before reaching the oceans due to use of freshwater resources in the basin The upper limit of accessible blue water resources is estimated at ~12500–15000 km 3 yr -1. Physical water scarcity is reached when withdrawals of blue water exceed 5000–6000 km 3 yr -1. Some stats

5. Image courtesy and source: http://www-g.eng.cam.ac.uk/

6. Threat to human water supply and aquatic water needs(Blue water) The loss of soil moisture resources due to land degradation, deforestation, threatening terrestrial biomass production and sequestration of carbon(Green water) Impacts on climate regulation due to decline in moisture feedback affecting regional precipitation patterns. Threats to human livelihood

7. Water available is very less The pressure on global freshwater resources is growing rapidly, mainly due to increasing food demands For the reasons mentioned in previous slides Need to define the planetary boundary

8. Control Variable:Blue water usage in km 3 yr -1. Planetary boundary: <4000 km 3 yr -1 State of Knowledge: 1. Scientific evidence of ecosystem response but incomplete and fragmented. 2. Slow variable, regional or subsystem thresholds exist. 3. Proposed boundary value is a global aggregate, spatial distribution determines regional thresholds Proposed planetary boundaries

9. Image source: Internet