Midterm #1

Habitable/Goldilocks Zone

orbital zone where a planet can have liquid water

Thermosphere

Absorbs some high energy UV and x-ray radiation

Mesosphere

Gases thick enough to slow down meteors

Stratosphere

Contains ozone that blocks most UV radiation

Troposphere

Where all weather occurs

Carbon Dioxide

Lasts centuries in the atmosphere. Measured in ppm, currently measured at 440 ppm. Comes from fossil fuels, volcanoes, forest fires.

Methane

Lasts 7-12 years in the atmosphere. Measured in ppb. Livestock/manure, decay, landfalls and wetlands, permafrost. 60% of methane comes from human sources.

Nitrous Oxide

Comes from fertilizers, fossil fuels, fires. Roughly 40% of emissions come from fertilizers/agriculture.

Chlorofluorocarbons - CFCs

Caused hole in ozone layer. 1986 Montreal Protocol regulated CFC production. Largely used in industrial/refrigeration uses.

Water Vapor

Weak but abundant. Not a cause, but a response and accelerant.

Atlantic Meridional Overturning Circulation (AMOC)

The “conveyer belt” circulating the water in the ocean. Starts in the North Atlantic and takes roughly 1000 years. Slowing due to ocean warming.

Positive Feedback Loops

Self Reinforcing. Albedo effect, melting permafrost, water vapor warming, deforestation.

Negative Feedback Loops

Self Regulating. Ocean CO2 absorption, chemical weathering

Emissions by Sector - Energy

73%

Emissions by Sector - Agriculture

18%

Emissions by Sector - Industry

5.2%

Emissions by Sector - Waste

3.2%

Drought

Causes: Positive feedback loop of soil dryness, decreased winter snowpack means less summer meltwater.

Solutions: Zai holes. Water pools in holes instead of runoff. Manure attracts termites that overturn soil.

Fire

Causes: Longer dry seasons. Pine beetles, droughts, and fire suppression increase fuel load.

Solutions: Controlled burns.

Sea Level Rise

Causes: Melting ice on land and water expanding as it warms. Risen 8-9 inches since 1880.

Hurricanes/Tropical Storms

Causes: Warming ocean temps cause more storms and higher sea levels cause higher storm surge waterlines. Tropical storms could see a decrease in frequency but an increase in intensity.

Solutions: Restoring wetlands and reefs, such as the Chesapeake Bay Oyster Reef.

Extinction (Land)

Predicted ~30% extinction. Amphibians, mammals, and birds most at risk.

Climate Circulation Slowdown

Greenland ice melting is weakening AMOC. Gulf Stream slowdown causes east coast sea level rise and extreme weather in Europe.

Ocean Acidification

Caused by increased carbon dioxide in the ocean. Carbonate/chalk shells dissolve, affecting corals, bivalves and plankton. Historically acidification leads to marine extinction.

Ocean Warming

Increased disease and metabolism, changes in storms and habitat sustainability. Warm water holds less oxygen. Causes coral bleaching.

Deoxygenation

Oxygen minimum zones (omz) are expanding. Caused by eutrophication, warming, and slowdown of ocean currents.

Ocean Extinctions

70-90% decline in coral reefs with 1.5 degrees C of warming. Roughly 1/3 of marine species rely on coral reefs at some point in their lives. Also caused by overfishing.

Responses to Climate Change

Move, Adapt, Die

Move

Most species today are moving. Generally up mountains, towards poles, or to deeper water.

Velocity of Climate Change

How far a species would need to move each year to avoid the effects of climate change. Marine species are moving 6x faster than terrestrial species.

Adapt

Individuals may adapt, but it is difficult for whole populations. Most species cannot adapt fast enough.

Die

Local or global extinctions. Likely if species live at the edges of their geographic ranges.

Extirpation

Population extinction, such as California leopards.

Extinction

Death of all populations. Global.

Kill Mechanism

Process hypothesized to cause mass extinction event. Ex. trophic cascade with the dinosaurs (not asteroid).

Extinction Selectivity

Data on which species survive vs. go extinct. Provides evidence for kill mechanism.

Common Traits of Extinction Selectivity

Geographic range size, body size, niche breadth (specialist vs generalist), r vs k select species. There are higher rates of extinction in the tropics.

Niche vs. Range Size

Niche: can use a wider array of resources

Range Size: less affected by disasters

Modern Extinction Kill Mechanisms (Five Largest)

Agriculture, Logging, Invasive Species, Urban Development, and Overexploitation/Direct Take

Agriculture and Logging

Kill Mechanisms: deforestation, habitat destruction, habitat fragmentation, pesticides, irrigation diverting water.

Remediation: sustainable logging, thinning over clear cutting

Invasive Species

Kill Mechanisms: competition for resources, kill local species, spread disease

Remediation: promote native species, physically removing IS, quarantine new species, agriculture checkpoints, boat sanitization

Urban Development

Kill Mechanisms: clears species, habitat fragmentation, light/sound/chemical pollution, habitat loss

Remediation: wildlife crossings

Overexploitation/Direct Take

Kill Mechanisms: hunting and fishing

Remediation: protected areas, farmed fishing, hunting permits, captive breeding of pets, avoiding insect art/jewelry, using peat moss substitutes

Extinction Severity

How many taxa (at a given rank) died.

Taxonomy

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Taxon

Group of organisms.

Background Rate

Average extinction rate excluding mass extinctions. Averages 5 families per million years, but has gone down over the last 600 Mya.

Diversity

A count of taxa from any given period. Diversity = Origination (speciation) - Extinction

Origination

Process of new species arising (speciation). Average rate is 0.05 - 0.2 new species per million years.

John Phillips (1860)

Made the first diversity curve.

Making Diversity Curves

Look up first and last occurrence in record then count how many overlap in each time unit. Observed diversity is influenced by the fossil record and human error.

Norman Newell (1960)

Mapped the diversity rate and brought attention to the major diversity losses. Later argued that there are 5 major diversity declines.

Ordovician Extinction

444 Mya. 86% species lost.

Devonian Extinction

360 Mya. 75% species lost.

Permian Extinction

250 Mya. 96% species lost.

Triassic

200 Mya. 80% species lost

Cretaceous Extinction

65 Mya. 76% species lost.