Natural Disasters Final

climate

Characteristic atmospheric conditions over a long period of time (years or decades)

weather

Atmospheric conditions over a short period of time (days or weeks)

permanent gasses

Gasses whose proportions stay constant (nitrogen or oxygen)

variable gasses

Gasses whose proportions vary with time and space (carbon dioxide, water vapor, ozone, methane, nitrous oxide)

aerosols

Microscopic liquid or solid particles whose proportions vary with time and space

cryosphere

The part of the hydrosphere where water stays frozen year-round

What are examples of the cryosphere?

-permafrost

-sea ice

-ice caps

-glaciers

-ice sheets

glacier

A thick mass of ice that originates on the land from the accumulation, compaction and recrystallization of snow

What are four types of glaciers?

1-valley (alpine) glacier

2-ice sheet

3-ice caps

4-ice shelves

What percentage of Earth's land is covered by glacial ice today?

10%

When was the most recent Ice Age?

2.6 million years ago

During which division of geologic time did the most glacial stages occur?

The Pleistocene epoch

Does glaciation cause sea-level rise or drop?

Drop

Glacial-interglacial cycles occurred every ______ years

100,000

About ____ of these cooling-warming cycles have been identified

20

Lake Bonneville was a _____ lake

pluvial

In what type of climate did pluvial lakes form?

Cooler and wetter

Name 5 Pleistocene animals that roamed North America

1-Wooly Mammoth

2-Mastadon

3-Saber-toothed cats

4-Giant ground sloths

5-Camels

Possible cause of glaciation: ___________ hypothesis

Milankovitch

Shape (________) of Earth's orbit varies

eccentricity

Angle of Earth's axis (_____) changes

obliquity

Earth's axis wobbles (_______)

precession

How much have the mean annual temperatures risen over the last decade?

A] 14°C

B] 1.4°C

C]0.14°C

B] 1.4°C

The rise in temperature has caused a rise in sea level of ______ inches over the past century:

A]40-80"

B] 4-8"

C] None Yet

B] 4-8"

What area of the globe is experiencing the greatest warming?

The Arctic

How do seafloor sediments provide evidence for climate change?

They record sea-surface organisms, which change with climate

How does the ratio of oxygen isotopes provide evidence for climate change?

Glacial ice is enriched in ¹⁶O, and during Ice Ages the concentration of ¹⁸O in seawater is enhanced. These ratios are reflected in CaCO₃ shells

Why do glacial ice cores provide evidence for climate change?

Air bubbles trapped in the ice records changes in CO₂ and methane concentrations

Do corals provide evidence for climate change? Why or why not?

Yes, they exhibit seasonal growth bands

Do greenhouse gases raise or lower the temperature of Earth's surface? Why?

GHGs raise the temperature because they re-radiate energy back toward Earth

Where does coal come from?

Plant material

Where does oil come from?

Typically remains of buried marine plankton

CO₂ concentration data prior to 1958 came from air bubbles trapped in ____

ice cores

What level (in ppm) did CO₂ surpass in 2013?

400ppm

In addition to CO₂, name three other greenhouse gases:

1-methane (CH₄)

2- nitrous oxides

3- CFCs & HFCs

What GHG is released when permafrost melts?

CH₄ (methane)

Positive feedback mechanisms _____ global climate change

amplify

What are consequences of global climate change?

1- global warming may increase intensity of storms

2-wildfires are becoming more frequent & intense

3-oceans are becoming more acidic

4-sea level is rising

wildfire

self-sustaining, rapid, high-temperature biochemical oxidation reaction

Ash is made of ______

mineral compounds

Soot is made of ________

unburned carbon

Wildfire requires:

1-Fuel

2-Oxygen

3-Heat

[True/False] Wildfire reverses the process of photosynthesis

True

What are the three phases of a wildfire?

1-preignition

2-Combustion

3-Extinction

preheating

Fuel loses water and other volatile compounds

pyrolysis

Processes that chemically degrade fuel

What happens during preignition?

Fuel achieves temperature and water content favorable to ignition

Does ignition always lead to wildfires?

No, sufficient fuel must be present

What are the two types of combustion occurring during a wildfire?

Flaming combustion and smoldering combustion

extinction

The point at which combustion ceases

What three factors explain the behavior of a large wildfire?

1-fuel

2-topography

3-weather

What weather factors affect wildfires?

-temperature

-relative humidity

-atmospheric stability

-wind speed/direction

-precipitation

Fires usually burn most intensely in the ________

midafternoon

What topography factors affect wildfires?

-elevation

-position on slope

-aspect

-shape of landscape

-steepness of slope

Fuel on the _______ facing slopes are usually drier and burn more easily

south

What fuel factors influence wildfires?

-size and shape

-moisture content

-horizontal continuity

-vertical continuity

-chemical content

[True/False]

Large woody material burns more easily than pine needles

False-pine needles burn more

What is a ground fire?

A fire that creeps along under the ground surface - little flaming, more smoldering

What is a surface fire?

A fire that moves along the surface - burns slowly with smoldering, limited flaming

What is a crown fire?

Flames are carried along tree canopies - driven by strong winds and steep slopes

How do fires affect erosion?

Fires remove anchoring vegetation on steep slopes, leading to more erosion and landslides

What are the atmospheric effects of a wildfire?

Fires contribute to smog formation, as well as the release of smoke, soot and gases

How are wildfires related to climate change?

Climate change increases the intensity and frequency of fires

What is an example of vegetation that benefits from wildfire?

Bearberry uses fire to propagate - the seeds need heat from the fire to open

What are some benefits of wildfires to plants and animals?

-removal of surface litter for grasses

-recycles nutrients in system

-animals benefit from increased plant life

How can the hazards of wildfires be reduced?

-enforce building codes, ban burning and fireworks, prescribed burns, insurance, evacuation

Where are asteroids found?

In the asteroid belt between Mars and Jupiter

Define meteoroids

Broken up asteroids

Define meteors

Meteoroids that enter Earth's atmosphere (shooting stars)

Define meteorites

Meteors that hit Earth's surface

What is the speed that objects enter Earth's atmosphere?

7 to 45 miles per second

What is an airburst?

A meteoroid that explodes in the atmosphere

What was interesting about the Chelyabinsk airburst in 2013?

It was the largest known asteroid to enter Earth's atmosphere since Tunguska airburst in 1908

Why was the Chelyabinsk asteroid not observed before it struck the Earth?

Meteor astrophysicists were tracking a different asteroid

What was the most powerful natural explosion in recent Earth history?

The Tunguska asteroid, releasing energy equivalent to ~185 Hiroshima bombs

What are the craters on the Moon so well preserved?

The moon has no geological activity or erosion so craters are not erased.

Define mass extinction

Sudden loss of large numbers of plants and animals relative to number of new species being added

What are three possible triggers for a mass extinction?

1-plate tectonics

2-volcanic activity

3-meteorite impact or airburst

How many major mass extinctions have occurred?

Six

During the Great Permian Extinction ___% of all vertebrate species on land and ___% of marine organisms were destroyed

70%

90%

What is the possible cause of the Great Permian Extinction?

Large basaltic volcanic eruptions in Siberia

What animal thrived after the Permian Extinction?

Reptiles

What is the Mesozoic often called?

"Age of Reptiles"

For how many years did dinosaurs rule the land?

180 million years

How long have the modern form of humans been around?

200,000 years

Besides dinosaurs, what other organism ruled during the Cretaceous Period?

Giant crocodiles

It is estimated that ___ of all plant and animal species went extinct at the end of the Mesozoic

3/4

What is thought to have caused this extinction?

A large meteorite strike at the Yucatan Peninsula 65 million years ago

What evidence is there for an asteroid collision 65 million years ago?

1-cm thick layer of sediment containing high level of iridium

What is the shorthand for the Cretaceous-Paleogene boundary?

K-Pg (used to be termed the K-T boundary)

How big was the crater in the Yucatan peninsula?

125 miles in diameter and 25 miles deep

What were some of the devastating effects of this impact?

-dust and debris blocks sunlight

-sulfuric acid enters atmosphere

-fireball sets off wildfires around the globe

-tsunamis reach over 1000 ft high

What is happening on Earth one month after the impact?

-there is no sunlight and no photosynthesis

-acid rain

-food chain has stopped

What is happening on Earth several months after the impact?

-sunlight returns

-acid rain stops

-ferns restore burned landscape

How often do impacts of this size occur?

Once every 40 to 100 million years

In the Cenozoic ___________ replace the reptiles as dominant vertebrate life forms on land

mammals

In the Cenozoic mammal groups became very large. What are some examples of these large mammals?

-wooly mammoths

-giant ground sloths

-saber toothed tigers

What is special about the La Brea Tar Pits in Los Angeles?

The tar pits trapped over 650 species of Ice Age animals such as the mammoth, plus one human skeleton

When did the Pleistocene epoch end?

11,000 years ago

What was the climate like in the Pleistocene?

Warmer as evidenced by the ice sheets and glaciers receding