Global Climate Change Midterm 2

Insolation

• Incoming Solar Radiation per unit area

• 2.5x greater at the equator than at the poles because sunlight hits the equator more directly 

• Uneven heating drives global wind and ocean circulation

Atmospheric Layers - Troposphere

0-10 km; weather occurs, temperature decreases with height

Atmospheric Layers - Stratosphere

Ozone layer, temperature increases with height

Atmospheric Layers - Mesosphere

Meteors burn up; temperature decreases again

Atmospheric Layers - Thermosphere 

Auroras; temperature increases sharply 

Atmospheric Layer - Exosphere

Outer layer, mergers with space

Atmospheric Layers - Tropopause 

The boundary between troposphere and stratosphere 

Wind and Convection - What causes wind and convection currents in Earth’s atmosphere 

Uneven heating of Earth —> warm air rises at the equator (low pressure), cool air sinks at the poles (high pressure)
- Air moves from high —> low-pressure, forming winds and convection currents that redistribute heat around the planet

Circulation Cells - Hadley Cell

0-30; rising at equator, descending near 30

Circulation Cells - Ferrel Cell

30-60; mid-latitude mixing cells

Circulation Cells - Polar Cell

60-90; cold, sinking air at poles, rising near 60.

What do the circulation cells form

Together they form Earth’s global wind belts

What is the Intertropical Convergence Zone (ITCZ) and where is it found? 

• ITCZ is where the Hadley Cells from each hemisphere meet near the equator

• Warm and moist air rises —> heavy rainfall and thunderstorms 

• It shifts north and south seasonally with the solar equator 

Coriolis Effect

Breaks global circulation into three smaller cells (hadley, ferrel, and polar)

Why are there three circulation cells per hemisphere?

If Earth didn’t rotate, each hemisphere would have one large convection cell, because of earth’s rotation, moving air is deflected:

• right in the northern hemisphere

• left in the southern hemisphere

What is the relationship between air temperature and water vapor?

Warm air holds more water vapor than cold air

• when air cools to its dew point, it becomes saturated and condensation begins, forming clouds and precipitation 

El Nino

Weaker trade winds —> warmer pacific ocean —> northern US warmer and drier

La Nina

Stronger trade winds —> cooler pacific ocean —> northern US colder and wetter 

What does IPCC stand for and what does it do?

Intergovernmental Panel on Climate Change; it is a UN body that assesses and communicates global climate science through regular Assessment Reports (ARs)

How do climate models operate as 4-D models?

They simulate climate change in three spatial dimensions (latitude, longitude, altitude) and add time as the fourth dimension

• Equations for energy, moisture, and gases are solved repeatedly to show how the climate evolves

How are climate models validated for accuracy?

Models are tested by hindcasting - running them backward using past conditions. If they reproduce historical climate patterns accurately, they’re considered reliable for future projects 

SSPs stands for?

Shared Socioeconomic Pathways

SSP1

Sustainability; green growth, low inequality, renewable focus

SSP2

Middle of the road; Continuation of current trends

SSP3

Regional Rivalry; Fragmented world, slow progress

SSP4 

Inequality; wealthy nations adapt; poor nations struggle 

SSP5

Fossil-fueled development; high economic growth via fossil fuels, high emissions

How many Gt CO2 was emitted globally in 2023?

37.5 Gt

Top 3 Carbon Polluting countries

China, USA, India (In that order)

Biggest sources of energy around the world?

Oil, Coal, Gas