The hydrological system
The hydrological system
You should have an understanding of the impact of human activity on the hydrological cycle:
You should have an understanding of how the oceans redistribute heat through surface and deepwater currents
These currents play an essential role in regulating the climate and supporting fish stocks and coral reefs. Any significant changes in ocean currents are likely to destabilise many other living systems.
Ocean circulation systems are driven by differences in temperature and salinity. The resulting difference in water density drives the ocean conveyor belt, which distributes heat around the world, and thus affects climate.
Warm currents flow on the surfaces of the oceans, the cold currents are deeper.
The 'Gulf Stream' which is the warm current flowing from the Caribbean northwards brings warmer water to Northern Europe and moderates its climate.
Groundwater depletion examples
A new model simulating regional groundwater dynamics and withdrawals from 1960 to 2100 found that:
The Colorado River no longer reaches the sea
Read fig 4.21 to answer the following questions in full sentences:
Use this Guardian article to answer the following questions:
The River Nile
The River Nile has 2 main tributaries (Blue and White Nile) and flows through several African countries. Egypt, South and North Sudan are almost completely reliant on the Nile for their freshwater supplies. With very little rainfall, rising populations and increasingly energy intensive industries and lifestyles the Niles water is more important than ever.
Ethiopia and Sudan also have rising populations and a need for more electricity and water for irrigation. They have both talked about damming the Nile, closer to its sources. Doing this could have major implications for water security in Egypt and North/South Sudan. Ethiopia is in the process of building a hugely contraversial dam - The Grand Reneissance Dam.
Watch the video and makes notes about the following:
Case Study: Newfoundland Cod Fisheries
Restrictions in place on Cod Fishing in Newfoundland:
An Harvest Control Rule (HCR) for cod has been in place since 2007, though the directed fishery has been under moratorium since 1994 to give the stock an opportunity to rebuild...Since the Atlantic cod is a recovering stock, there are interim and long-term management objectives.
The fishery will remain closed until there is a “very low” probability—defined as less than 10 percent likelihood—of being below adult biomass targets. Once the fishery can reopen, the catch limit will be set to result in continued growth. For the Atlantic cod, adult biomass has increased considerably since 2010. Therefore, the fishery remains closed and bycatch is “restricted to unavoidable bycatch.”
Case Study: Icelandic Cod Fisheries