Planet Earth TEST 3

What are cup carbonates?

Believed to have formed due to acid rain, lay right on top of glacial deposits.

What happened 15k years ago in regards to continental realignment?

Bering Bridge broke, separating Russia and Alaska. Also Greenland from Canada.

When is the next glacial period supposed to begin?

Not for thousands of years. The Earth is slowly receiving less and less solar radiation over the past 12,000 years. Reconstructing shows that Earths temperature has been decreasing over the past million years.

Do sunspots have a large impact on solar radiation?

Not really. It's smaller.

Why does the sun keep getting hotter?

Nuclear fusion. Fusion of atoms (hydrogen creating helium) creates burst of energy.

Where does carbon go during glacial times? Explain.

Oceans. No plants in glaciers. 1. CO2 transferred to ocean from land 2. CO2 is more soluble in cold ocean 3. Ocean biological activity increased by dust fertilization

What layer of the Earth protects us from UV rays?

Ozone

On a graph, what do the peaks and valleys of the ice age temperature changes represent?

Peaks are interglacial periods. Valleys are glacial.

What eon and era are we in?

Phanerozoic (192Ma), Cenozoic

Which North Star does Earth see now?

Polaris

What period do we live in? Is it glacial or interglacial?

Quaternary, Interglacial

Without greenhouse gases, what would the temperature of the Earth be? What is the temp now?

-30 degrees Celsius. Earth is not frozen due to the carbon cycle, which keeps the Earth at 15 degrees celsius. Greenhouse gases brought the temp up to 18 degrees but carbon furthers the heat.

What is Earth's average albedo?

0.3

How is CO2 concentration increasing?

1. Burning of fossil fuels. (cars, industrial plants) 2. Deforestation-Trees store CO2 and when trees are cut down and burnt, that CO2 is released back into the environment. Also less trees take in less CO2 so that increases levels.

What evidence do we have for the icehouse world?

1. Glacial deposits in rocks that used to be in the tropics (dropstones-rocks that were part of the crust that rafted onto an iceberg and eventually dropped to the seafloor) 2. Global tropical distribution of sites with similar glacial deposits (we know their past because of paleomagnetism) 3. Events are synchronous (dated) with the same events.

How do we know ice sheets existed in such big size and volume?

1. Ice Sheet Size Reconstruction-Vertical crust motion(post glacial rebound) and glacial deposits (erratic blocks and moraines that can only be explained by glacial activity) 2. Ice sheet volume reconstruction-Isotope O16 and O18. 18 heavier than 16 and less easily evaporated. 16 was precipitated as snow and ice. Huge displacement of water.

What are 5 significant differences between LGM and today?

1. Ice sheets were at least 15,000 sq km. 2. Sea level-way lower at last glacial maxim,. Sea level was about 125 meters lower than today. Ice melted to become ocean water. This precipitation used to be snow used to create glaciers. 3. Land bridges-parts of continents used to be touching each other. Bering strait connected Russia and Alaska. People came to the Americas from Asia over this bridge. 4. Biotic Changes-animal and plant species were different (woolly mammoths and saber-toothed creatures) 5. Atmospheric changes-CO2 concentrations were lower in LGM. Glacier periods had an average of 180-190 ppm as opposed to the average of 270 ppm in interglacial times.

How do they count the number of sunspots?

1. Number of Groups (n1) 2. Number of Individual Spots (n2) Use formula n1 X 10 + (n2)

What are the four controls on Earth's temperature?

1. Sun temperature 2. Distance from the sun (changes over time) 3. Albedo (how much radiation is reflected)*changes depending on glaciers and climate 4. Greenhouse effect

So how exactly is what humans did in relation to CO2 traceable?

1. Timing-1750 (Industrial Revolution with coal burning) Technology would not have advanced with fossil fuels, but its time to find alternative synchronous with fossil fuels. We can calculate exactly how much CO2 has been released into the atmosphere by tracing all of the fossil fuels used. 2. Isotopes (oxygen and CO2 concentration are traceable) Fossil fuels are made from plants living in swamps. Plant matter accumulates into peat. Peat progressing mineralized to become lignite. Lignite becomes coal.Since peat is old plants and algae and they are full of CO2, we are just releasing more C02 into the atmosphere. Coal is enriched in C12 and depleted in C13. This changes the signature of the atmosphere through burning.

What are the cycles in the number of sunspots?

11 years

What is the solar constant on the sun?

1366 Watts/meter^2

What is the range of sunspot size?

15-115,000 km.

What is the temperature difference between sunspots and sun?

2,000 kelvins. sun is 5,700 and sunspot is 3,700 k.

When did the Quaternary period being? How would you describe the period?

2.6 Ma. An ice age characterized by a general trend of climate deterioration (decreasing temperatures) and high variability.

What is the Earth's current obliquity?

23.5 degrees

How much solar radiation actually reaches Earths surface?

239 W/m^2

What sunspot cycle are we currently in?

24; Lowest sunspot number in over 100 years

What is the amount of solar radiation that reaches Earth's atmosphere?

341 Watts/meter^2

How much surface radiation is emitted by Earth? How much of that is emitted by the atmosphere? How much of that is outgoing radiation?

356 W/m^2. 169 W/m^2. 239 W/m^2

How has carbon changed over time?

400ppm CO2 in atmosphere. CO2 fluctuated at 400-100 million years ago. C02 has gone down over time, but has risen again. Last time CO2 was this high was 5 million years ago.

What is the latest CO2 reading?

406.23

How much warmer are interglacial periods than glacial periods?

5 or 6 degrees on average

What is ice sheet growth positive feedback?

A cascading effect. The build up of ice sheets causes the land below to depress because of its great weight. The asthenosphere moves under the crust and it depresses about a kilometer. As a glacier grows upward, the ice expands because of the cold temperatures at the high elevation. The ice also has high albedo so it doesn't absorb solar heat and melt, it just reflects it.

How frequent are interglacial periods?

About 1 every 100,000 years

What is today's CO2 concentration?

About 400 ppm.

Why doesn't Earth absorb all of the solar radiation that reaches the atmosphere?

Albedo. The reflectance of solar radiation averages at about 30% on the surface. Ice alone has a reflectance of 90-95%. Darker surfaces, like asphalt have low albedo.

What is the Hothouse Earth?

Although no weathering went on during the snowball Earth, the tectonic processes were still underway and volcanic depressing and CO2 buildup in the atmosphere. Earth slowly warming up. Eventually the greenhouse effect became strong enough to start melting the ice. The ice melted, then there was lower albedo, then more solar radiation came in, then there were warmer temperatures, then there were massive amounts of meltwater then lots of weathering. The weathering could not keep up with CO2.

What is the carbon pump?

An oceanic mechanism. Sand dunes in Sahara and Australia. Glacial periods are arid, cold and windy. Sand picked up by the strong winds become iron fertilizer for the ocean. More aridity=more dust=more nutrients=more photosynthesis. Dust is a good fertilizer for algae. Photosynthesis pumps carbon out of the atmosphere. Increased photosynthesis in surface waters, most of the absorbed carbon makes it to deep waters. Carbon sinks.

How are ice ages global events?

As CO2 levels go up and down because of the atmosphere is a homogenous reservoir of CO2 it affects the temperature everywhere. Ice sheet growth is mostly in the North because of Milankovitch but the whole planet is affected by the CO2 levels.

How is ice sheet melting also positive feedback?

As the ice retreats, the bedrock pushes the crust back up. The melting ice cap waters have a low albedo and absorb the solar radiation and cause the glacier to melt even more. Since the ice is trapped in a self-created depression, it cannot escape the melting from solar radiation.

How do direct measurements work in CO2 reconstruction?

Based on daily measurements of CO2 started by Scientist Keeling in 1958. Measured at Mauna Loa observatory in Hawaii. Follows Northern Hemisphere patterns because it has the most land mass and most photosynthesis.

What is weathering?

Breaking down of rocks.

What is sun luminosity?

Brightness and intensity of sun

How much do Greenhouse gases warm the temperature of the Earth?

By 33 Kelvins. From 255 to 288.

How much have carbon dioxide levels changed in the last 250 years?

C02 concentration was 270 ppm before the Industrial Revolution. Current C02 concentration is 400 ppm. Last time it was this high was 5 Ma.

Explain carbons dissolution in water.

CO2 dissolves more easily in cold water. 10x more ppm dissolved in 1 degree decreases of temperature. Atmosphere loses 30% of its CO2 to the ocean.

What happens to CO2 in the ocean?

CO2 elements create shells of organisms that need them. These elements die and become seafloor that be traced and aged by scientists.

How does CO2 change with seasons? Day and night?

Carbon levels go way down in May because plants start taking in a lot of CO2 for photosynthesis. Create plant tissues. After this, CO2 starts building up until the next May. CO2 levels go down at night because there is no sun for photosynthesis.

What are the Milankovitch cycles? What are the three aspects of the Milankovitch cycles?

Changes in distance between the Earth and Sun over time. Eccentricity (orbit), obliquity (tilt) and precession (spin).

What are sunspots?

Cold regions of the sun that have intensified magnetic activity. Vary in size/shape and come and go.

As a recap, what are convection and conduction?

Convection is the physical movement of heat. Conduction is the transfer of heat through solid material.

What are iridium deposits?

Cosmic particles that have accumulated on top of ice sheets for millions of years. Sandwiched between glacial deposits and cup carbonates.

What are the three key methods of CO2 Reconstruction?

Direct Measurements (keeling curve), Ice Core Bubbles, Stomatal Density of Plants

What is the snowball Earth?

Earth completely covered in ice and slush. Happens during Faint Young Sun. The continents were all around the subtropics (650 Ma). Sun hits directly near the equator and the C02 hits the Earth and the weathering is intense. CO2 buries itself in the ocean. Weathering should've slowed down with cooler temps. Weathering doesn't work around the equator and ice starts forming in the tropics. The ice, which has high albedo is not absorbing the sunlight, but just reflects it. This further cools the Earth.

What is perihelion?

Earth is closest to the Sun.

What are the bright areas around sunspots called?

Faculae

How do ice core bubbles work for CO2 reconstruction?

Found in Antarctic domes. Lots of scientists take core samples from Volstok drilling station where the ice is 400,000 years old. Very thick ice and diamond drill bits are used to get cores. Similar retrieval to marine sediment cores. Scientists examine the bubbles under microscope and track the carbon from the samples to a time period. These samples show carbon levels from a much older time period than direct measurements. By examining the chemical signature of the ice, they can tell the ocean temperature. Hydrogen and Deterion (hydrogen with neutron) are shown in different ice levels. Deterion sinks due to heavier weight and is found in colder temperatures, where hydrogen has been evaporated.

Why is Earth's temperature higher than it would be with just solar radiation?

Greenhouse gases are greater than the process by which radiation from our planet warms the surface to a temperature above what it would be in the absence of an atmosphere. (Earth is heating up its own atmosphere with GHG)

When in aphelion, what are the glaciers doing?

Growing in the Northern Hemisphere because even in the summertime the Earth is so far away from the sun that the ice sheets are growing and the temperature is cold. Glacial periods.

What is carbonic acid?

H2CO3; Weak acid that slowly attacks rocks pf the crust and dissolves them. Rainwater combined with CO2 dissolves the rocks and CO2 is removed too.

What is the cycle of ice sheet melting?

High solar insolation-Ice sheet melts-bedrock rebound delayed for thousands of years-ice sheet stays at lower, warmer elevations-More negative ice mass balance-Ice melts faster

What characterizes interglacial periods?

High temperatures, low ice volume. More CO2.

What is the land to ocean transfer of CO2?

Ice destroyed biomass and carbon was washed into ocean. Ocean gains carbon concentration. Vegetation loses about a quarter of its CO2. Plants take in C12. Oceans absorbed C13 because it is heavier. Isotope signature in trees is depleted of C13, negative values. C13 and C12 in the ocean levels are equal. This carbonated biomass is traceable in the ocean.

What does aphelion and small tilt allow ice sheets to do?

Ice sheets grow over 80,000 years. Coldest since it is the farthest away from the sun.

Do we live in an icehouse world or hot-house?

Ice. Ice sheets are on the planet. Quaternary period characterized by glacial and interglacial periods where the ice amount fluctuates.

Why is this referred to as a paradox?

If the sun was cooler, Earth should've been ice in the beginning, but we know during the Hadean era, the Earth was hot and had a lot of volcanic activity.

How is the carbon cycle like Earth's thermostat?

If you set a thermostat to 75 degrees, when it gets cooler than 75 degrees outside the thermostat will turn up the heat to maintain that 75 degrees. Since the Earth is now receiving stronger radiation, there are less or weaker greenhouse gases since the sun is heating the Earth more effectively.

When in perihelion, what are the glaciers doing?

It is close to the sun so the ice sheets are melting. Interglacial periods.

How is solar constant calculated? What is the sun's luminosity? What is Earth's distance from the sun?

L/4(PI x d^2); Luminosity is 3.9x 10^26 Watts. Distance is 150,000,000 km.

What is LGM?

Last Glacial Maximum. Glacial time with most geological evidence because it was only 21,000 years ago. Right before the current interglacial. Called the Wisconsonian ice sheet because it expanded as far as Wisconsin. About 30% of the land mass was covered by ice, including most of Canada, Northern US, Scandinavia, Siberia, Russia, Southern Australia and New Zealand and Antarctica.

Where does Earth derive its energy from?

Less than 1% from internal heat (convection and conduction. 99% from external heat (solar radiation)

What is the cycle of ice sheet growth?

Low solar insolation-Ice Sheet grow-Bedrock sinking delayed for thousand of years-Ice sheet stays higher, colder elevations-More positive ice mass balance-Ice grows faster

What happens as the climate gets cooler (like going into a glacial period)?

Lower temp, less precipitation, less vegetation and weathering will slow down.

Why is Mauna Loa a good location for direct measurements?

Mauna Loa has good reliability because it has elevation, surrounded by all Pacific Ocean, has strong winds and low human CO2 releases.

What does perihelion and large tilt allow ice sheets to do?

Melt. Warmest summers.

What are responsible for interglacial and glacial periods?

Milankovitch Cycles

How do GHG's on Earth compare with other planets?

Moderate. Mercury has low GHG. Venus has high.

What happened in the Maunder Minimum from 1650-1750?

No sunspots. A little ice age happened. Temperatures dropped and glaciers got bigger. There was less irradiance and UV radiation from the sun. Less ozone formation and increased volcanic activity.

Do sunspots play a role in global warming?

No; Data says we currently have a low number of sunspots. Also, the temperature of the Earth has increased but the number of sunspots has not. No correlation.

Did Earth's thermostat work well during the Faint Young Sun Era?

No; Earth experienced major swings.

Is the Earth today hotter than it has ever been?

No; It has been much warmer. In fact, the last interglacial period had warmer temperatures.

What are the three ways sun radiation can be taken on Earth's surface?

Reflected-sent back into space. Like in places with high albedo. Absorbed-Taken in. Refracted-changes direction of propagation.

What kind of electromagnetic waves does the sun emit?

Short wave UV, visible light, near infrared

What might hinder the next glacial period or might even cause a complete skip?

Since 1850, carbon dioxide has caused increase in temperatures in the arctic. Solar insolation is dropping but temperature is rising.

How does stomatal density of plants contribute to CO2 reconstruction?

Stomata are like skin pores. They absorb carbon dioxide and release water and oxygen. When there is a lot of CO2, there is low stomatal density. Low CO2 has high density because stomata need to store more C02 because it is more rare. By studying fossilized plants, you can trace the CO2 levels. Stomatal density decreases exponentially with atmospheric CO2 concentration.

What is Aphelion?

Sun is farthest away from Earth.

What is the faint, young sun paradox?

Sun was much more faint than it is today. Sun has become hotter and brighter over time. The sun is nearly 70% brighter today than it was 4.5 billion years ago.

What happens with the Earth's precession?

The Earth's spin has a 26,000 year cycle. Earth rotates around its axis and wobbles. The wobbling of the Earth around its own axis. The North Star changes between Polaris and Vega.

What happens with the Earth's obliquity?

The Earth's tilt has a 41,000 year cycle. The Earth moves from 22.1 degrees to 24.5 degrees. When the Earth is more tilted, it receives a lot more sunlight to one pole and the seasons are a lot stronger (colder winters, warmer summers). When the Earth is less tilted, there is less seasonality.

What is the 2C (3.5 F) tipping point?

The Paris Climate accords agreed that we don't want to change the C02 levels dramatically as to cause worldwide disfunction. The temperature worldwide has increased a degree Celsius. Scientists doubled the CO2 ppm in preindustrial era and called this the tipping point, came back and declared 450 ppm the maximum tipping point. At the point, there is a 50/50 chance that the CO2 levels could cause dramatic climactic effects. The goal by 2030 is to reduce CO2 release by 42.0 metric tons or two degrees. In the agreement, countries pledged to reduce amount to 56.2 metric tons of C02. The US pledged to reduce their 2005 emissions by 25%. If the countries don't stick to their agreement, 65 metric tons of CO2 could be released. *In 2017, President Donald Trump backed out of the Paris Agreement

What is Uniformitarianism?

The Present is the key to the Past.

What is the holocene?

The current epoch that started 12,000 years ago. Holocene is interglacial period in an Ice Age.

Why are CFC's banned in the US?

The destroy the ozone layer and create smog.

Where does weathering displace C02?

The ocean

What happens with the Earth's eccentricity?

The orbit around the sun has a 100,000 year cycle. Every year the Earth orbits a little farther away from it. Two distinct parts: Aphelion and Perihelion.

How does the Carbon cycle work?

There is an initial change, that forms a warmer climate, temperatures, precipitation, and vegetation increase, chemical weathering also increases and increased CO2 removal by weathering eventually creates the reduction of the initial warmth.

True or False: We are in a naturally warm period of time.

True

True or False: We live in an ice age.

True

What happened 10k ago in the US in regards to ice sheets?

US completely uncovered by ice sheet.

Using Earth's absorption of solar radiation, the temperature of Earth should be much higher than it is, what is the difference?

Using the solar radiation formula, Earth should be at 255 K (or -18 degrees Celsius). It is actually 288 Kelvins. (15 degrees Celsius)

What best characterizes the quaternary period?

Very dramatic climate changes

What are glacial periods known for?

Very good at erosion. Changes landscaping. (Ex: Great lakes only existed 20,000 years ago as the Big Glacier retreated to the North and created depressions and lake basins). Low CO2 in atmosphere Lots of Ice Sheets

What are the greenhouse gases?

Water vapor, CO2, CH4, CFC, ozone and nitrous oxide.

What is radiation?

Waves that travel through empty space.

Why do people say that we have unprecedented temperatures today?

We have increasing sea surface and surface temperatures over the past few decades. These are the warmest ever RECORDED. This data only goes back about 150 years.

Describe the early Earth. How does that compare to the Modern Earth?

Weak solar radiation. Strong greenhouse gases and CO2 in the atmosphere; Strong solar radiation, weak greenhouse gases and CO2 in rocks.

What are the increased carbon levels doing?

Weathering is happening very quickly. More CO2 removed from the atmosphere and into the ocean.It takes Earths 10's of 1,000's of years to adjust to such change. Ice sheets are melting. More melt water resulting from the ice caps melting and even higher elevation glaciers are melting. When the ocean gets warmer, sea levels are higher. Lots of flood and droughts.

What is relationship between ice volume and CO2 concentration?

Well correlated. More C02 means less ice and vice versa.

Can you calculate the greenhouse gases on other Planets?

Yes

Do a higher number of Sunspots affect solar radiation?

Yes, the bright faculae that surround the sunspots create a high irradiance. Therefore, more sunspots equals more irradiance.

Does Earth emit its own radiation?

Yes. The planetary energy balance can help find that out.

Where are sunspot number observed? Who first observed sunspots?

Zurich observatory using Fraunhofer refracting telescope. Galileo first observed sunspots.