Climate Change & Hydrology Flashcards
What are 3 big issues facing water?
- Water availability/aquatic ecosystem health
- Integrated watershed management in response to climate variability and climate change
- Separating the impacts of human influence from natural climate variability and climate change
What are 7 recent changes seen in the hydrological cycle?
- Increased cloud cover since 1990s
- Precipitation more variable and increase since 1900s
- 8% decline in snow cover in NA since 1970’s
- Sea level rise of 2.4mm/yr due to human intervention (0.54mm) and ice melt
- Increase in fall-spring stream flow (more flooding?)
- 77% river flow affected by diversions and reservoirs (dams increased 700% storage volume and tripled residence time)
- Sediment transport doubled (16% in reservoirs)
When is it estimated that the world will face a global water deficit?
By 2030
What is the mitigation scenario for Representative Concentration Pathways?
2.6W/m^2
What is the ‘burn baby burn’ scenario for Representative Concentration Pathways?
8.5 W/m^2
What are the projected climatic changes to the hydrological cycle?
- More intense storms and flooding and extreme winds
- More evapotranspiration, drier vegetation and soils
- More frequent and severe droughts, increased wildfires
- Sea level rise, coastal erosion, saltwater intrusion
- Water in streams and lakes warmer
- Earlier runoff, less summer stream flow
- More rain less snow
- Reduced or eliminated glaciers, increased high elevation erosion
- More precip in some ares, less in others, increased variability
Observations of climate changes from AR4 (points to AR5)
- Oceans
- Warming sea surface temps
- Warming oceans
- Increased surface humidity
- Change in ocean salinity
- Acidification of oceans
- Increasing rates of global mea sea level rise
Observations of climate changes from AR4 (points to AR5)
- Land
- More frequent warm days and nights, fewer cold
- Reductions in number of frost days
- Decreasing snow cover in most regions
- Degrading permafrost in areal extent and thickness
- Large scale precip changes
- Increase in number of heavy precip events
Observations of climate changes from AR4 (points to AR5)
- Ice
- Shrinking annual average arctic sea ice extent
- Widespread glacier retreat
- Changes in ice sheets in Greenland and Antarctica
What will the water cycle in a warmer world be driven by?
- Increased evaporation rates
- Greater moisture capacity of warm air
Not everything is predictable, but what changes are certain?
- More intense rains
- Stronger global hydrological cycle (increased evap and specific humidity)
- Shifts in convection enters and global-scale distribution of precip as circulation patterns adapt to increased energy in system
- Increased potential evapotranspiration
- Less global snow and ice (permafrost and glaciers)
What can we determine if they projected models agree?
- That we have more confidence in the model but that doesn’t mean that it is correct
What are the expected changes in the Cryosphere?
- Arctic sea ice cover shrinks and thins year round
- Antarctic expected to decrease in sea-ice extent and volume
- Average Arctic sea-ice reductions
What is the projected Arctic sea-ice reduction for RCP 2.6 (mitigation)
- 34%
What is the projected Arctic sea-ice reduction for RCP 8.5 (burn baby burn)
- 94%
