6B - Stores and Flows
Climate change affects both stores and flows, size of snow and glacier mass, reservoirs, lakes, amount of permafrost, soil moisture levels as well as rates and runoff and stream flow.
Stores
Surface runoff and stream flow
- More low flows (droughts) and high flows (floods)
- Increased runoff and reduced infiltration
- Uncertain, because of abstraction by humans
Flows
Reservoir, lake and wetland storage
- Changes in wetland storage cannot be conclusively linked to climate change
- It appears that storage is decreasing as temperatures increase
- Possibly little change, with higher precipitation and evaporation cancelling each other out
- Uncertain, as soil moisture depends on many factors, of which climate is only one
- Where precipitation is increasing, it is likely that soil moisture will also increase.
- Deepening of the active layer is releasing more groundwater
- Methane released from thawed lakes may be accelerating change
- Decreasing length of snow-cover season
- Spring melt starting earlier
- A decreasing temporary store
- Strong evidence of glacier retreat and thinning since the 1970s
- Less accumulation because more precipitation is falling as rain
- A decreasing store
- More data on surface temperatures needed
- Where there is ocean warming, there will be more evaporation
- Possibly ocean warming leads to the generation of more cyclones
- Storage capacity being increased by meltwater
- Rising sea level