Table 9. Lessons learned in dealing with climatic extremes.

Category Lessons learned
General lessons learned in dealing with climatic extremes Recent climate variability and change seem to have increased flood and drought hazards in many regions.
The higher adaptive capacity of the society, the more resources it can provide to cope with extreme events, and the less tragic are the consequences of climate hazards.
Risk assessment of climatic hazards is necessary.
Public education and distribution of information on climatic hazards, e.g., risk maps, etc., are important.

Lessons learned in dealing with floods Floods occur all over the world, even in arid regions.
A large flood may recur again soon. As shown by several recent examples, there is a common misconception among the general public about, e.g., a so-called 100-year flood.
Enhancing water storage, especially underground, mitigates both types of extremes: floods and droughts.
Structural measures such as building dikes and straightening rivers also have negative effects, including the shifting of flood problems downstream, adverse ecological impacts, and high maintenance costs.
There is often a false sense of security and an over-reliance on flood control works such as levees, reservoirs, etc., which in reality provide protection only below a certain threshold.
Human experience of a flood tends to reduce the amount of damage caused by the following flood, especially if it occurs within a short period of time.

Lessons learned in dealing with droughts It is often becoming difficult to increase the amount of water in storage because of its decreasing availability in general, and the adverse environmental and social impacts of reservoirs.
Intensive groundwater withdrawal may ensure social and economic development over a long period of time and thus provide an alternative solution for drought management, although some undesirable impacts may result from intensive pumping, e.g., water-table depletion, groundwater quality degradation, negative effects on streams and wetlands, or land subsidence.
Enhancing water storage, especially underground, mitigates both types of extremes: droughts and floods.
Adequate water management laws could improve drought preparedness in many regions.