- Climate change occurs on various timescales and is influenced by factors like solar activity, Earth's orbit, atmospheric composition and greenhouse gases, volcanic eruptions, and human activities like fossil fuel burning.
- Evidence from geology and fossils shows past climate changes, including intervals warmer than today and ice ages. The last ice age peaked around 20,000 years ago and glaciers have since retreated.
- Future climate is uncertain but computer models predict global warming and changing precipitation patterns if CO2 doubles from current levels due to feedbacks like ice-albedo and water vapor effects. Careful study of past and present helps understand complex climate system.
Climate science part 3 - climate models and predicted climate changeLPE Learning Center
Many lines of evidence, from ice cores to marine deposits, indicate that Earth’s temperature, sea level, and distribution of plant and animal species have varied substantially throughout history. Ice cores from Antarctica suggest that over the past 400,000 years global temperature has varied as much as 10 degrees Celsius through ice ages and periods warmer than today. Before human influence, natural factors (such as the pattern of earth’s orbit and changes in ocean currents) are believed to be responsible for climate changes. For more, visit: http://www.extension.org/69150
Here you can find the Ocean circulation, as it is happening by natural activities, Coriolis effect will occur due to the wind pattern and changes in the ocean floors.
The Earth’s climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events—like heavy rainstorms and record-high temperatures, are already taking place. One important way to track and communicate the causes and effects of climate change is
through the use of indicators. An indicator represents the state or trend of certain environmental or societal conditions over a given area and a specified period of time. This lesson highlights all those indicators for a better understanding of climate change.
Impact of climate change in atmosphere of oceanAshish sahu
How does climate change effect the ocean?
5 ways that climate change affects the ocean
Higher temperatures are bad for fish — and for us.
Polar ice is melting.
Rising sea levels represent a slow, seemingly unstoppable threat.
Warming oceans alter currents.
Climate change is affecting the chemistry of seawater.
AS Level Physical Geography - Rocks and WeatheringArm Punyathorn
The earth's surface is an ever-changing entity. With the forces of weather and climate and tectonic variability, the rocks and minerals that make up the earth are always changing in size, shape and forms - a fascinating, ancient, never-ending process.
Climate science part 3 - climate models and predicted climate changeLPE Learning Center
Many lines of evidence, from ice cores to marine deposits, indicate that Earth’s temperature, sea level, and distribution of plant and animal species have varied substantially throughout history. Ice cores from Antarctica suggest that over the past 400,000 years global temperature has varied as much as 10 degrees Celsius through ice ages and periods warmer than today. Before human influence, natural factors (such as the pattern of earth’s orbit and changes in ocean currents) are believed to be responsible for climate changes. For more, visit: http://www.extension.org/69150
Here you can find the Ocean circulation, as it is happening by natural activities, Coriolis effect will occur due to the wind pattern and changes in the ocean floors.
The Earth’s climate is changing. Temperatures are rising, snow and rainfall patterns are shifting, and more extreme climate events—like heavy rainstorms and record-high temperatures, are already taking place. One important way to track and communicate the causes and effects of climate change is
through the use of indicators. An indicator represents the state or trend of certain environmental or societal conditions over a given area and a specified period of time. This lesson highlights all those indicators for a better understanding of climate change.
Impact of climate change in atmosphere of oceanAshish sahu
How does climate change effect the ocean?
5 ways that climate change affects the ocean
Higher temperatures are bad for fish — and for us.
Polar ice is melting.
Rising sea levels represent a slow, seemingly unstoppable threat.
Warming oceans alter currents.
Climate change is affecting the chemistry of seawater.
AS Level Physical Geography - Rocks and WeatheringArm Punyathorn
The earth's surface is an ever-changing entity. With the forces of weather and climate and tectonic variability, the rocks and minerals that make up the earth are always changing in size, shape and forms - a fascinating, ancient, never-ending process.
Climate: Climatic Change - Evidence, Cycles and The Futuregeomillie
A PowerPoint used in class to cover the key forms of evidence you need to know for the Exam. Key Questions are likely to be focused on how we can gain information of past climatic change, and how it can be used to predict future, and I would expect you to be able to comment on the usefulness of the different types. For instance, Ice cores are highly accurate and quantifiable evidence, but gaining them is expensive, and only gives a climatic record for the site at which the snow formed. However, they do provide the longest record of change.
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions, or in the distribution of weather around the average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors such as biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. Certain human activities have also been identified as significant causes of recent climate change, often referred to as "global warming"
Scientists actively work to understand past and future climate by using observations and theoretical models. A climate record — extending deep into the Earth's past — has been assembled, and continues to be built up, based on geological evidence from borehole temperature profiles, cores removed from deep accumulations of ice, floral and faunal records, glacial and periglacial processes, stable-isotope and other analyses of sediment layers, and records of past sea levels. More recent data are provided by the instrumental record. General circulation models, based on the physical sciences, are often used in theoretical approaches to match past climate data, make future projections, and link causes and effects in climate change.
Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects.
Multiple lines of scientific evidence show that the climate system is warming.
Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures. Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation
2. Introduction
Climate change is the change in the statistical
properties of one or more atmospheric
variables
• Climate changes on many different time scales
• Climate change is greatest at the Earth’s poles
and least in tropical regions
• Understanding climate change requires
understand the physical cause or causes of the
climate change
3. The Geologic
Column
Human history starts
Pleistocene ice
ages
Dinosaurs are wiped
out
High sea level
stands during the
Cretaceous
Major extinction
of life
High sea level
stands during the
Paleozoic
First multicell animals
Age of Earth - 4.6 billion years
Past climates in Earth
history can be inferred from
geologic and fossil evidence
4. Warm Intervals and Ice Ages
• For most of Earth’s history, climate was 5-
15oC warmer than present, and ice was rare
• Brief cold ice ages interspersed generally
warm climate
–Over past 2.5 billion years, ice ages
occurred only 10-20% of the time
5. The Earth began a gradual
cooling phase about 55
Mya. Ice accumulated on
Antarctica about 34 Mya.
By 10 Mya, Antarctica
was covered with ice. By
4 Mya, so was Greenland.
The Earth has
demonstrated regular
glacial/interglacial cycles.
The Earth currently is in
a warm phase. The last
glacial phase peaked
about 20,000 years ago.
6. The last interglacial may have been the
warmest time in Earth history
• Peaked ~ 125,000 years ago
• Air temperature about 2°F to 5°F warmer
than present
• Sea levels about 20 feet higher than at
present
8. Ice extent during the last glaciation
During the last glaciation, North America was covered with ice more than 2 miles
thick in places; the ice extended as far south as St. Louis, Missouri. Sea level was
more than 300 feet lower than today. The extent and thickness of the ice is
estimated from geologic evidence.
9. Ice extent about
20,000 years ago;
the glacial ice
started retreating
about 15,000
years ago; the ice
readvanced about
13,000 years ago
for about 1200
years during the
Younger Dryas
period
10. Ice extent
about
20,000
years ago;
the ice left
New
England
about
12,000
years ago
11. Earth Temperatures for the last 1000 years
Medieval warm period
Little ice age
Current
warming
12. July moisture Tidewater region of Virginia and North Carolina
Historic
climate; dry
periods
affected early
North
American
settlements
13. The shorter term
Dansgaard-Oeschger
cycles and longer-term
Bond cycles attempt to
explain the regularity of
warming and cooling
events during the past
150,000 years. These
cycles are probably
caused by changes in
ocean circulation,
atmospheric circulation,
and insolation.
14. Factors Involved in Climatic Change
• Variations in
– Insolation intensity
–Earth’s orbit
–Land surface changes
–Atmospheric and aerosol composition
15. Variations in solar output
• Solar output regularly changes
– 0.1-0.2% change due to sunspots
– 11 year cycle for sunspots
• The Maunder Minimum was a period of few sunspots
and lower solar activity around the year 1600
–The Little Ice Age occurred during the Maunder
minimum
–Links to the quasi-biennial oscillation (QBO)--
changes in stratospheric tropical winds associated
with changes in sunspots
16. Early faint Sun paradox
• The geologic record shows warmer early
Earth temperatures, but astrophysical models
show that the sun was about 1/3 weaker than
today
–The early warmth was probably caused
by greater CO2 concentrations in the early
Earth atmosphere
17. Milankovitch Cycles -- Precession
Milankovitch cycles -- regular natural variations in the
Earth’s orbit around the sun
–Obliquity -- 41,000-year period
–Eccentricity -- 100,000-year period
– Precession -- 27,000-year period
18. Changes in land configuration and surface
characteristics
• Plate tectonics gradually changes the
configurations of the mountains and oceans
• Mountain building and land erosion affect
climate over geologic time
• Land use changes such as deforestation and
desertification change albedo, surface
temperatures, and water balance
19. Changes in atmospheric aerosols affect the
amount of solar energy that can reach the
Earth’s surface
• Major volcanic eruptions inject great
amounts of aerosols into the atmosphere
over days or weeks, leading to temporary
climate cooling
• Residence times of tropospheric aerosols is a
few years
• Residence times of stratospheric aerosols is a
few decades
21. Ship tracks
over the
Pacific leave
clouds in their
exhaust trails
(excess
condensation
nuclei)
22. Changes in radiation-absorbing gases
• Anthropogenic contributions of CO2
– Increased exponentially since the mid
19th century due to fossil-fuel burning
– Increased CO2 concentrations leads to
increased atmospheric absorption of IR
radiation
– Increased anthropogenic greenhouse
gases in the atmosphere can lead to
increased atmospheric water vapor (the
most important greenhouse gas)
23. • Exchange of CO2 between the atmosphere and
ocean
–Current CO2 emission rates increasing 3.5
ppm/yr
–The oceans are a major absorber of CO2 due to
oceanic biota photosynthesis and solution of
CO2 in the water
–Only about 1/2 of the anthropogenic CO2
emission ends up in the atmosphere (where
does the other 1/2 go?)
24. Feedback mechanisms are systems in which
changes in one variable lead to changes in
another
• Feedback mechanisms can be
–Negative, where the feedback acts to
inhibit further change in a variable
–Positive, where the feedback acts to
magnify further change in a variable
25. Examples of feedbacks
Ice-albedo feedback (positive feedback)
• Ice cover affects global albedo
Evaporation of water vapor (positive feedback)
• Water vapor is a greenhouse gas
Ocean-atmospheric interaction (positive or
negative feedback)
• Ocean levels change through thermal
expansion and glacial melting
27. Computer models of
global climate change
give predictions of
what future climate
might be. They take
into account the
climate/ocean
feedback mechanisms
that are known. This
climate prediction is
for double the
atmospheric CO2 over
current values.
28. This climate
prediction is for
double the
atmospheric CO2 over
current values. While
global warming
would be greatest at
the poles, changes in
the precipitation
patterns would be
much more diverse
across the Earth.
