Environmental Science

Unit 4 Overview

Tropical: Areas near the equator, receiving the most intense sunlight.
Polar: Areas near the earth's pokes receiving the least intense sunlight.
Temperate: Tropical and polar regions.

Archeological evidence indicates that our species emerged from African savannas and survived by gathering edible vegetation and hunting animals for food and clothing made from animal hides.
10,000 years ago, the earth’s climate warmed and humans began their transition from hunter-gatherers to farmers

What factors influence climate?

Key factors that influence an area’s climate are incoming solar energy, the earth’s rotation, global patterns of air and water movement, gasses in the atmosphere and the earth’s surface features.
Weather: Is a set of physical conditions of the lower atmosphere that includes temperature, precipitation, humidity, wind speed, cloud cover and other factors that occur in a given area over a period of hours or days.

Climate: Is the pattern of atmospheric conditions in a given area over periods ranging from at least three decades to thousand of years.

Human activities, such as large inputs of carbon dioxide (CO2) and other greenhouse gasses that alter the earth's natural greenhouse effect, can lead to climate change.

Greenhouse gasses: Play a role in determining the lower atmosphere's average temperatures and therefore the earth's climates.

Greenhouse effect: This natural warming of the lower atmosphere.

Earth's surface features affect local climates

Various topograaphical features of the earth's surface can create local climatic conditions that differ from the general climate in some regions.
When moist air blowing inland from an ocean reaches a mountain range, it is forced upward.
As the drier air mass passes over the mountaintops it flows down the leeward slopes and warms up.

Humans have disturbed much of the earth's land

60% of the world's major terrestrial ecosystems are being degraded or used unsustainably as the human ecological footprint get bigger and spreads across the globe. No one knows but there are increasing signs that we need to come to grips with this vital issue.

What are the likely effects of climate change?

Rapid atmospheric warming could have serious consequences
Humanity faces a rapid projected increase in the average temperature of the lower atmosphere during this century.

What is the nature of the atmosphere?

The two innermost layers of the atmosphere are the troposphere, which supports life and the stratosphere which contains the protective ozone layer.

Atmosphere: Life exists under a thick blanket of gasses surrounding the earth.

Troposphere: 75-80% of the earth's air mass is found here.
If the earth were the size of an apple, this lower layer containing the air you breathe would be no thicker than the apple's skin.

Greenhouse gasses: They absorb and release energy that warms the troposphere and the earth's surface.

Stratosphere: The second layer, contains less matter than the troposphere but its composition is similar.
The notable exceptions, contains much lower volume of water vapor and much higher concentration of ozone (O3).

Ozone layer: Filtering effect of ozone in the lower stratosphere acts as a "global suncreen" that keep about 95% of the sun's harmful UV radiation from reaching the earth's surface.
Helps protect us from sunburn, skin and eye cancers, cataracts and damage to our immune systems.
Perserving the stratospheric ozone layer should be one of humanity's top priorities.

How can we slow climate change?

We can reduce greenhouse gas emissions and the threat of climate change while saving money and improving human health if we cut energy waste and rely more on cleaner renewable energy resources.

Dealing with climate changeis difficult

Reduced global fire activity due to human demography slows global warming by enhanced land carbon uptake

Global fire due to human activities plays with the carbon cycle which has an effect on the planet's warming. CO2 is a greenhouse gas which traps heat in the earth’s atmosphere preventing heat from escaping. “Changes in fire emissions can feed back on the global carbon cycle, but whether the trajectories of changing fire activity will exacerbate or attenuate climate change is poorly understood.” researchers have concluded that if we keep up with our mitigation efforts today, we can “enhance land carbon uptake corresponding to offsetting ∼5 to 10 y of global CO2 emissions at today’s levels.”

I believe that right now we are at a pivot point, if we keep up with the changes and solve our issues we can see a brighter and cleaner tomorrow. It will only take a little over half a decade inorder to solve our problem. However there is no time better than now.

Wu, C., Sitch, S., Huntingford, C., Mercado, L. M., Venevsky, S., Lasslop, G., Archibald, S., & Staver, A. C. (2022). Reduced global fire activity due to human demography slows global warming by enhanced land carbon uptake. Proceedings of the National Academy of Sciences, 119(20). https://doi.org/10.1073/pnas.2101186119