Exam4Geo

What is photosynthesis?

The process by which plants convert sunlight into energy using CO₂ from the atmosphere.

How does increased atmospheric CO₂ affect plant growth?

It can enhance plant biomass growth if temperature and water availability are constant.

What can mitigate the benefits of higher CO₂ on plants?

Higher temperatures and reduced water availability.

What defines the groundwater balance?

Groundwater = Precipitation - Global Precipitation

How does global precipitation change with warming?

It increases by 1-3% per °C of warming.

How is groundwater affected by warming?

Evaporation increases, reducing groundwater by ~7% per °C.

Why can surface water become drier despite more precipitation?

Due to higher evaporation rates.

What defines a drought?

A period of low precipitation or high evaporation where water supply can't meet demand.

What is a feedback mechanism in drought?

Low moisture reduces atmospheric water vapor, worsening drought.

What is an example of long-term drought?

The Southwestern U.S. has had a 20-25 year drought, the worst in 1200 years.

How do plants affect the water cycle?

By transpiring water, they contribute to atmospheric moisture and total evaporation.

What happens when forests are removed?

Reduced precipitation and more frequent droughts due to loss of plant biomass.

What is river equilibrium?

When erosion and deposition rates are equal.

What is incision in river systems?

When erosion exceeds deposition, deepening the river bed.

What is aggradation in river systems?

When deposition exceeds erosion, building up the river bed.

What increases river energy?

Greater water volume and speed, influenced by landscape, dams, and precipitation.

What is the ocean's mixed layer?

The top 10–500m of ocean, affected by winds and sunlight.

What affects ocean water density?

Temperature (↓density), salinity (↑density), pressure (↑density).

What drives ocean currents in the mixed layer?

Winds, with current strength decreasing with depth.

Where do ocean currents diverge and converge?

Diverge at equator, converge at 30° N.

What is the Coriolis effect on currents?

Currents turn right in the Northern Hemisphere, left in the Southern.

Why is the Arctic warming faster than other regions?

Ice-albedo feedback causes it to warm 4x faster than the global average.

What are the main causes of sea level rise?

Melting ice sheets and thermal expansion of seawater.

How much has sea level risen and what's the projection?

Risen ~8 inches; projected to rise 2–6 feet by 2100.