Climate Section 3 Flashcards
What is the Earth’s current average temperature
15.8 degrees celsius, 60.44 degrees fahrenheit
What is a Climate Proxy
Preserved physical characteristics of the past that allow scientists to reconstruct the climate conditions in the past.
How are Tree Rings climate proxies
Patterns in tree ring widths, density and isotopic composition. 1 year per ring. The width of the rings determines the climate at the time.
How are ocean/lake sediment Cores climate proxies
Marine organisms have oxygen in them and their shells become fossilized.
How are Ice Cores climate proxies
They trap gas and dust and isotopes of oxygen
What is a Sunspot
when the sun’s magnetic field interacts with its photosphere, causing a dark and cooler area. These happen in an 11 year cycle and the energy output of the sun changes by 0.2%
What are some atmospheric composition changes
the atmosphere used to be mostly carbon dioxide, water vapor, nitrogen and methane which made the Earth really hot because of the greenhouse effect. Ocean algae took the carbon dioxide and turned it into oxygen, cooling the Earth
How do volcanic eruptions, comets and meteors effect climate change
When erupting, volcanoes release sulfur, ash, smoke and dust into the atmosphere which increases the albedo, or it reflects more solar radiation. Comets and meteors have a similar effect.
How do plate tectonics effect climate change
Land has less specific heat than water and so more land means that the Earth heats and cools faster than the oceans. Plate tectonics moving around the Earth affects this therefore.
Name the Milancovitch Cycles
Eccentricity, Obliquity, Precession
What is Eccentricity
The shape of the orbit of the Earth around the Sun. Normally the rotation of the Earth is usually circular but sometimes because of the gravitational pull of other planets it becomes more elliptical
What is an Aphelion
when the Earth’s orbit is elliptical, the place where the Earth is far away from the Sun.
What is a Perihelion
when the Earth’s orbit is elliptical, the place where the Earth is close to the Sun.
What is Obliquity
The angle of the Earth relative to it being straight upwards. Caused by the gravitational pull of the moon. This is a 41,000 year cycle from 22.1 degrees to 24.5 degrees. 22.1 degrees the Earth gets similar temperatures year round, 24.5 there are drastic temperature changes year round.
What is Precession
The direction of Earth’s tilt, not the degree/angle. This affects which hemisphere is facing the sun at which time of the year.
How does water’s temperature effect climate change
Water can hold more carbon dioxide when cold than hot. Cold water = colder weather. Hot water = hotter weather.
What is a Positive Feedback Loop
When a system of causes and effects eventually intensifies the original cause.
How are fossil pollen climate proxies
Pollen grain for each species have their own shapes and these shapes can be used to determine what kind of plant. The climate can be inferred by the type of plant.
How are Corals climate proxies
Their skeletons are built from calcium carbonate which has oxygen. Isotopes of oxygen can be used to find what temperature they were made in. Temperature can be used to find when it grew.
How is historical data climate proxies
Things like observations of past climate like farmer’s logs or newspapers can be used to determine the climate. Yields quantitative and qualitative results.
What is an Isotope
A family of elements which have the same number of protons but a different number of neutrons.
How are Isotopes used as climate proxies
Most oxygen atoms have a mass of 16 but some have 18. It’s easier for atoms with water and mass of 16 to evaporate then 18. The evaporated water eventually becomes snow, meaning that oceans are left with mostly mass 18 atoms.
What is a source (for carbon dioxide)
A way for carbon dioxide to be added to the Earth’s atmosphere (like burning fossil fuels)
What is a sink (for carbon dioxide)
A way for carbon dioxide to be removed from the Earth’s atmosphere (like photosynthesis)
