GEOS 5113 - GLOBAL CHANGE
Forests-climate feedback
-Through photosynthesis, forests remove CO2 from the atmosphere and store it as biomass -Forests absorb around 30% of CO2 emission annually -As the climate warms, forests become more susceptible to droughts, fires and disease. -Burned or decomposing trees release carbon to the atmosphere, further increasing atmospheric temperature.
positive feedback
(or reinforcing) feedback amplifies the change in the first quantity water vapor -warming as a result of the warming itself... EX: microphone too close to speaker EX: as frozen tundras and forests thaw, more c02 and methane is released.
Cosmic rays diagram
-14C and 10Be (beryllium) radionuclides are produced in a very similar way by nuclear reactions of cosmic ray particles with the atmospheric gases. After production, their fate is very different (system effects). --10Be attaches to aerosols and is transported within a few years to ground. --14C oxidizes to CO2 and enters the global carbon cycle, exchanging between atmosphere, biosphere, and the oceans.
Solar Variability and Varve Thickness
-A varve is an annual layer of sediment or sedimentary rock. -Varve means the whole of any annual sedimentary layer. More recently introduced terms such as 'annually laminated' are synonymous with varve. -An annual layer can be highly visible because the particles washed into the layer in the spring, when flow is stronger, are much coarser than those deposited later in the year. -This forms a pair of layers—one coarse and one fine—for each annual cycle.
The methane context
-After carbon dioxide (CO2), methane (CH4) is the most important greenhouse gas contributing to human-induced climate change. -For a time horizon of 100 years, CH4 has a Global Warming Potential 28 times larger than CO2. -Methane is responsible for 23% of the global warming produced by CO2, CH4 and N2O. -The concentration of CH4 in the atmosphere is 150% above pre-industrial levels (cf. 1750). -The atmospheric lifetime of CH4 is 9±2 years, making it a good target for climate change mitigation
Volcanoes and Climate
-Volcanoes blast large clouds into the atmosphere made up of gases and particles including sulfur dioxide, water vapor, and carbon dioxide. -In the atmosphere, water vapor and sulfur dioxide convert to sulfuric acid aerosols which reflect energy coming from the sun, thereby preventing the sun's rays from heating Earth's surface.
Best known tipping points
Amazon rainforest -5 years of c02 stored in amazon rainforest 200 billion tons of carbon -Greenland ice sheets Diff than arctic - land ice rises sea level not melting ice bergs because its already in the water -Coral bleaching Loses algae and secceptial to disese
Pacific Decadal Oscillation
An alternating pattern of sea surface temperature in the Pacific that reverses itself over periods of several decades. trend is cold temperatures at the sea surface and then that helps counteract the effect or CO2 in the atmosphere greenhouse gases in the atmosphere
Volcanoes and Climate (6)
An eruption can cause warming and cooling. An addition of carbon dioxide contributes to greenhouse warming. An addition to sulfurous gases induces cooling, because they turn into droplets of sulfuric acid that absorb and reflect sunlight and reduce the amount of heat that reaches the ground. But most documented cases show a net cooling effect.
feedback processes
Feedback processes are important in understanding climate variability and change -They can amplify or diminish the effect of a climate forcing and play an important part in determining the climate sensitivity and future climate state. -Feedback is the process in which changing one quantity changes a second quantity, and the change in the second quantity in turn changes the first.
Why Study Volcanic Eruptions and Climate?
It provides an analog for some parts of the nuclear winter theory --Rapid global aerosol transport and surface cooling from large aerosol loading provide natural analogs that support the nuclear winter theory. It allows us to separate the natural causes of interdecadal climate change from anthropogenic effects --The anthropogenic cause of recent global warming is strengthened after accounting for volcanic effects. The response to volcanic eruptions allows us to better understand the impacts of anthropogenic climate change on life --Biosphere responses and aspects of the carbon cycle have been clarified
2016 - global temperature
It was the hottest year on record One of strongest el ninos The coast of South America Causes madness everywhere else land and ocean temperatures
aki Eruption in Iceland
June 8th 1783 - Feb 7th 1784 -Second largest flood lava eruption in historical time -Iceland's biggest natural disaster -eruption was both tropospheric and stratospheric. lasted for 8 months, with continuous effusive emissions into the troposphere -Equivalent to 10 El Chichón-size eruptions -Reached heights of 10-13 km into the lower stratosphere. -Frequency distribution of cold summers, cold winters, and cold years in Europe and eastern United States during the period 1768 to 1798.
Global change - real
Land surface temp Sea surface Sea level
negative feedback
Negative (or balancing) feedback reduces the change in the first quantity
Permafrost feedback
Permafrost melts Creates methane Methane traps in heat More permafrost melts Continues on -the Arctic permafrost is rapidly thawing As it does, it accelerates microbial activity that releases CO2 and methane as a byproduct of digestion -Methane is 30 times more potent than CO2 in trapping heat. -As methane increase in the atmosphere, more premafrost thaws and more methane is released -super important for keeping temp/globe in check
Spatial variations in the prevalent climate
Various factors determine the average climate
carbon dioxide
a colorless, odorless gas produced by burning carbon and organic compounds and by respiration. It is naturally present in air (about 0.03 percent) and is absorbed by plants in photosynthesis. c02 stays in atmosphere much longer than methane -On a global scale, the amount of CO2 put into the atmosphere by respiration is equal to the amount of CO2 removed by photosynthesis. -Humans have changed the carbon cycle. -The burning of wood and fossil fuels adds more CO2 to the atmosphere.
Seasons
a good indicator of yearly variability each of the four divisions of the year (spring, summer, autumn, and winter) is marked by particular weather patterns and daylight hours, resulting from the earth's changing position with regard to the sun.
Water in the Atmosphere
bout 90% of water in the atmosphere is produced by evaporation, while the other 10% comes from transpiration from plants. Water accounts for between ~0% - 4% of the composition of the atmosphere and it is the most variable component. Given its residence time, water in the atmosphere is completely recycled around 40 times a year or every 9 days
global change
climate always changing the rate is alarming
Decadal Oscillations
climate cycles measured in spans of tens of years in terms of ocean modes of variability notions, they move very slowly.
Climate Trends
climatology focuses on trends too much greenhouse gases on Earth from burning fossil fuels=hotter Earth; caused by people Trend= Last Value-First Values/ number of years Trend= (10-9)/43 = 0.023 C per year
main feedback processes that are complicated to understand, but really important
clouds see ice water vapor in the atmosphere
How did sunspots play a role in the little ice age?
-Although there is no official cause of the little ice age, many scientists speculate that it was due mostly in part to low sunspot activity -Maunder Minimum was at its height from 1645 to 1715 -Sunspots could be seen by the astronomers of the day, such as Galileo
Increase in Net Primary Productivity (NPP)- CO2 Fertilization
-As higher concentrations of CO2 enter the atmosphere, plants have more material to photosynthesize (at first). -More plants take up even more carbon from the atmosphere, potentially reducing it. -But this fertilization effect diminishes with time as plants require other factors like nitrogen in the nutrient cycle. -High temperatures can negatively influence plant growth. -negative feedback
Greenhouse Gases
-Before the mid 18th century, GHG remained relatively constant. -As Britain and later the United States shifted from predominantly agricultural to industrial economies, the burning of coal, oil, and natural gas released GHG (mainly CO2) into the atmosphere. -Increasingly, as forests were cleared to make way for agricultural land, factories, and suburban housing, the amount of CO2 uptake by vegetation decreased. -As the quantities of CO2 and the other GHG in the atmosphere rose, the temperature of the atmosphere increased beginning around the 1850s and has accelerated since 1950. -This human-caused contribution of greenhouse gases is the enhanced greenhouse effect. -Carbon dioxide-66.15% -Methane-16.43% -Nitrous oxide-6.43% -Other direct GHGs-10.99%
Sunspots During Little Ice Age Continued
-Maunder Minimum caused a colder sun which also meant the sun would send out less warmth to the earth -During one 30-year span inside the little ice age astronomers observed only 50 sunspots -Whereas today astronomers see 40,000-50,000 sunspots in 30-year periods -During the little ice age the sun dropped in temperature by around ¼ of a percent
Volcanoes and Climate (4)
-The effect of an eruption on climate is greatest when the gas plume penetrates the stratosphere. -Unlike the lower atmosphere, the stratosphere does not have rain clouds as a mechanism to quickly wash out pollutants. -The aerosol plume will remain in the stratosphere for years until the processes of chemical reactions and atmospheric circulation can filter them out. -High-altitude winds can carry the particles and ash far from its origins.
Tipping points in the Climate system
-The point at which small changes are enough to cause a larger, more critical change that can be abrupt, irreversible, and lead to cascading effects. -The concept of tipping points was introduced by the IPCC 20 years ago -It was thought then they would occur if global warming reached 5°C. -Recent IPCC assessments suggest that tipping points could be reached between 1°C and 2°C of warming.
Volcanoes and Climate (3)
-Volcanoes can significantly impact the weather but only the major eruptions will have noticeable effects on the climate. -Most major eruptions cause a temperature change of a fraction of a Kelvin, which does not sound like much, but over an entire year it represents a large amount of heat subtracted from the Earths budget. -Volcanic emissions make up less than 1% of annual global CO2 emissions (USGS).
hydropower plants (dams) - methane
-both carbon dioxide and methane are released when vegetation decomposes under water (dams). -There are enormous differences from facility to facility due to a range of varying reservoir features and meteorological characteristics -Some hydropower reservoirs are carbon sinks, taking in more carbon through photosynthesis by organisms living in the water -Others have carbon footprints equal to or greater than, fossil fuels. Timeframes matter: -After 50 years of operation, a hydropower facility could cause less than 40% of the warming that would be caused by a coal-fired plant.
Chaiten volcano
-captured by NASA's Terra satellite at 10:35 a.m. local time on May 3, 2008. -Before 2008 it had erupted 9,400 years ago -Its ash plume reached 15 km in height
solar variability and climate change-online answer
-suns total energy output at all wavelengths is not constant -Numerical global climate models predict that only a 1% change in the Sun's energy output could significantly alter the mean temperature of the Earth-atmosphere- land-ocean system
10 indicators of a warming world
1. Air temp 2. Water vapor 3. Temperature over ocean 4. Sea surface temperature 5. Sea ice decreasing 6. Sea levels 7. Land temperature 8. Snow cover 9. Glacier and Ice sheets 10. Ocean heat index
What is the science supporting climate change? (2)
1. earth is warming2. rising global T have been accompanied by changes in rainfall, intense rain, more floods, and droughts, as well as more frequent and severe heat waves
2021 - global temperature
20 separate billion-dollar weather and climate disaster events across the US. Total cost $145.0 billion: the 3rd most costly year on record, behind 2017 and 2005. The total costs for the last five years ($742.1 billion) is more than one-third of the disaster cost total of the last 42-years (1980-2021) This reflects a 5-year cost average of nearly $148.4 billion/year — a new record — as shown on the left by the black line. 2021 is the seventh consecutive year in which 10 or more billion-dollar weather and climate disaster events have impacted the United States.
snow-albedo feedback
A positive feedback whereby increasing surface air temperatures enhance the melting of snow and ice in polar latitudes. This reduces the earth's albedo and allows more sunlight to reach the surface, which causes the air temperature to rise even more.
Volcanoes and Climate (5)
Because they scatter and absorb incoming sunlight, aerosol exert a net cooling effect on the Earth's surface. The Pinatubo eruption increased aerosol optical depth in the stratosphere by a factor of 10 to 100 times the levels prior to the eruption. Aerosol optical depth is a measure of how much light, airborne particles prevent from passing through a column of atmosphere. Over the next 15 months, scientists measured a drop in the average global temperature of about 0.6oC
Solar and Earth's surface Radiation
Both the Sun and the Earth emit continuous radiation spectrums The wavelength distribution is a function of the body's temperature
Temporal variations in the prevalent climate
Changes occur at various timescales
forcings vs. feedback
Create an initial change in the climate vs. Act to amplify initial forcings
Weather vs. Climate
Daily atmospheric conditions (temp and precip) vs long term atmospheric conditions the spatial distribution of climates globally depends on latitude, how close to the equator it is
Volcanoes and Climate (2)
Dark dust particles absorb sunlight, and light-colored aerosols reflect sunlight. The amount of heat reaching the Earth and temperature at the surface are reduced. The particles also affect our views of the sun and moon by scattering certain kinds of sunlight and letting other kinds through the atmosphere This can cause spectacular sunrises and sunsets The sun and moon may seem to be wrapped in halos or to glow with strange colors.
Ben Franklin (2)
During the summer of 1783, when the effect of the sun's rays should have been greatest, there existed a constant fog over Europe and North America. This fog was of a permanent nature; it was dry, and the sun seemed to have little effect towards dissipating it, as they do a moist fog, arising from water. Of course, their summer effect in heating the earth was diminished. --Hence the earth was early frozen, --Hence the first snows remained on it unmelted and received continual additions. --Hence the air was more chilled, and the winds more severely cold. --Hence perhaps the winter of 1783-4, was more severe, than any that had happened for many years. The cause of this universal fog is not yet ascertained. (One of his hypotheses) It was the vast quantity of smoke, long continuing to issue during the summer from Hecla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain.
This is the coldest/snowiest couple of weeks in decades: Global Warming is exaggerated. T or F
F: A warmer atmosphere holds more water that eventually precipitates somewhere in the form of water, snow or ice
Climate has always changed. It's natural. T or F
F: Current anthropogenic carbon release rate is unprecedented. The rate of temperature rise is 10 times faster than that of the last mass extinction (56 million years ago).
There is too much scientific uncertainty, thus we can't trust/use climate models' projections to act. T or F
F: Models have predicted warming very well since the 1980s
Climate change isn't that bad. T or F
F: Taken as a whole, the range of published evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time. - Intergovernmental Panel on Climate Change
We need innovative ideas and technology to reduce and reverse the amount of CO2 in the atmosphere, instead of reducing consumption of fossil fuels. T or F
F: we need both
positive feedback-video - top 4
Ice- melting Permafrost- decay of organic matter from this in the northern hemisphere Forests- increased droughts and forest fires atmosphere- abruptions to the jet stream too much co2 and methane warms the atmosphere
Why was the summer of 1783 so warmover Europe?
If it was caused by the eruption, there are several possibilities: 1. Circulation anomalies induced by radiative forcing from volcanic gases and aerosols. 2. Radiative anomalies from the sulfate aerosols caused warming (effect on cloud formation) 3. SO2 that had not converted to aerosols acted as a greenhouse gas.
Schwabe Cycle
Plotting sunspot counts, Schwabe saw that peaks of solar activity were always followed by valleys of relative calm—a clockwork pattern that has held true for more than 200 years. -Cosmic rays cause high level clouds to form => cooling -"active" sun produces more solar wind that deflects cosmic rays => warming -cycles see combinations of solar intensity overlaid with changes in cosmic ray concentration as we move around the galaxy
Tambora in 1815 (and an eruption from an unknown volcano in 1809), produced the "Year Without a Summer" (1816)
Released 100 million tons of SO2. Mt. Tambora also happened during the Dalton Minimum, increasing the cooling effects already occurring from low sunspot activity. There was a temperature drop of close to 0.5 Kelvins. Temperatures in New England dropped an estimated 1-2 Kelvins, it snowed in July. Tambora changed the climate so much that crops in Europe and north America failed in the following years. Tens of thousands of people were killed by the apocalyptic eruption, subsequent tsunamis and ensuing starvation and disease.
Solar modulation of flood frequency in central Europe
River Ammer flood frequency in the discharge record and solar activity. -(a) Frequency of River Ammer floods during MJJA with discharges between the 90th and 95th percentile and as above the 95th percentile. -(b) River Ammer flood frequency composite and total solar irradiance (TSI) . The black line indicates the original River Ammer flood frequency composite. -The blue lines represent the River Ammer flood frequency composite shifted for 2 and 3years into the past, revealing significant correlations with TSI.
Sea Ice Albedo Feedback
Sea ice has a much higher albedo than water. The decline in sea ice strongly affects how much solar energy is absorbed by the surface. More absorption -positive feedback
Stratosphere
Similar gas composition to the troposphere, except for lower water (1,000 times less) and much higher ozone concentrations. The ozone layer (17 km -30 km) is the result of oxygen atoms reaction with ultraviolet radiation(UV). These chemical reactions convert UV radiation into heat. This process also keeps 95% of harmful UV radiation from reaching the earth's surface This natural sunscreen protects us from sunburn, skin and eye cancer, cataracts and damage to our immune system
400 years of sunspot observations
Sunspot number observations. Since 1749, continuous monthly averages of sunspot activity have been available from the Solar Influences Data Analysis Center, World Data Center for the Sunspot Index, at the Royal Observatory of Belgium. -These are based on an average of measurements from different worlds observatories. -Prior to 1749, sporadic observations of sunspots are available.
Maunder Minimum
Sunspots cause occasional ferocious eruptions of electrified gas and light More sunspots usually means an increase in solar activity During Maunder Minimum the sun expands and its rotation is slowed
greenhouse effect - physics
The Sun's energy hits half of the Earth's area at any given time Emits uniformly over its entire surface. The annual incoming solar radiation at the top of the atmosphere averaged over the Earth is 340.4 W/m2 -Many gases exhibit "greenhouse" properties. Some of them occur in nature --water vapor, carbon dioxide, methane, and nitrous oxide --others are exclusively human-made (fluorinated gases) -Also called the "heat-trapping gases
atmosphere - main points
The atmosphere is mostly transparent to solar shortwave radiation; roughly 45% reaches the surface and heats the planet. The Earth's surface radiates longwave upward, but gases and water vapor in the atmosphere efficiently absorb radiation in the infrared range and trap much of it in the lower atmosphere. This is one mechanism whereby the atmosphere acquires heat. The air then radiates in all directions, including much of it downward to the Earth surface.
Atmospheric concentration
The atmospheric concentration growth rate has increased steadily.The high growth in 1987, 1998, & 2015-16 reflect a strong El Niño, which weakens the land sink.
climate sensitivity
The extent to which rising GHG affect the Earth's temperature, or how much warmer the planet will get if the amount of GHG in the atmosphere doubles -According to the IPCC report, our climate sensitivity is somewhere between 2 and 5oC (between 3.6 and 9oF) -This range sounds is wide because of factors that can speed up or slow down atmospheric warming --The main ones are clouds, sea ice, and water vapor -These factors are "feedback effects," and they can make predicting the planet's future climate very complicated -With no feedback effects at all, our climate sensitivity would be just 1℃
Terrestrial sink
The land carbon sink, estimated by Dynamic Global Vegetation Models, was 11.2 ± 2.2 GtCO2/yr during 2011-2020 and 10.7 ± 3.6 GtCO2/yr in 2020.
water vapor feedback
The net effect of increasing water vapor in global warming. Consists of the stronger positive feedback due to increased specific humidity and the weaker negative feedback caused by decreasing saturated adiabatic lapse rate. -Accounts for 66% to 85% of the GHG effect, compared to a 9% to 26% for CO2. -Is not the cause of climate change. -Its concentration in the atmosphere is limited by air temperature
Ocean sink
The ocean carbon sink, estimated by Global Ocean Biogeochemical Models and observation-based data products, continues to increase 10.2 ± 1.5 GtCO2/yr for 2011-2020 and 11.0 ± 1.5 GtCO2/yr in 2020
The ocean's solubility pump
The solubility pump refers to the ocean's ability to transport carbon from its surface to the interior. -The ocean serves an important role in regulating CO2 by dissolving it in water. -As ice sheets melt, carbon storage increases. -Currently, oceans absorb 33% of CO2 emitted to the atmosphere. (this process cannot continue indefinitely: solubility pump efficiency depends on ocean circulation) -negative feedback
Using the Pinatubo eruptionto test climate feedback mechanisms
The timing and amplitude of future global warming depend on the sensitivity of the climate system. The impacts of global warming depend on the response of various natural and human systems to climate changes. Pinatubo was a short, but large, perturbation to the climate system. While we cannot use it to test long-term processes, such as changes in the thermohaline circulation, we can take advantage of it to examine some short time-scale feedback processes and impacts.
Radiation
The transfer of energy by electromagnetic waves is an electromagnetic wave and is able to pass through the vacuum of space. Radiation carries energy which is converted to heat when it hits another object and is absorbed
Two main emission windows:
Visible spectrum centered at 0.5 microns Infrared spectrum centered at 10 microns Absorption by CO2 and water vapor overlaps at 15 microns and the Earth's surface emits strongly in this wavelength.
Volcanic Explosivity Index
Volcanoes have the capacity of throwing cubic kilometers of ash and debris into the atmosphere which can significantly alter the climate for years at a time- this is measured by the Volcanic Explosivity Index (VEI) The scale is logarithmic. An increase of "1" indicates an eruption 10 times more powerful than the number before it on the scale.
Methane - sources
Wetlands Termites The Oceans Hydrates Energy Landfills Ruminants Waste Treatment Rice agriculture Biomass burning
EFFECTS OF LARGE EXPLOSIVE TROPICAL VOLCANOES ON WEATHER AND CLIMATE
When proxy records of Northern Hemisphere climate change are corrected for the diffuse effect, there is no impact on climate change for time scales longer than 20 years. However, it appears that there was a hemispheric cooling of about 0.6oC for a decade following the unknown volcanic eruption of 1809 and Tambora in 1815, and a cooling of 0.3°C for several years following the Krakatau eruption of 1883. Volcanic eruptions provide a strong, yet brief perturbation to the climate system. The study of their effects on climate helps us to better understand this system and the impacts of climate change on us and allows us to make better predictions of future weather and climate.
Sunspots Cycle
dark spots on the surface of the sun where intense magnetic activity takes place. -Regular 11- year sunspot activity cycle -They prevent hot gasses from the interior of the star from reaching the surface -The overall effect of sunspots is positive. -The sun emits more light. -The disappearance of sunspots makes for a cooler sun. -When sunspot activity is at a minimum it is also referred to as Maunder Minimum. -Total solar irradiance changes over a 11-year cycle reaches amplitude of 0.1%. This variation is estimated to impact Earth's temperature by a few hundredths of degrees Celsius. -More sunspots, more solar energy -0.1% brighter when solar activity is high
Rice agriculture - methane
doubled in the past 45 years. --feeds 1/3 of World's population --methanogenesis - bacteria in warm, waterlogged soil releases methane. --0 -100 million tons/yr. Possibly biggest anthropogenic source. Solutions many rice varieties can be grown under much drier conditions improved varieties of rice, higher yield per acre.
Heinrich Schwabe
first to determine 11 year cycle of sunspots -Quiet suns come along every 11 years -It's a natural part of the sunspot cycle, discovered by German astronomer Heinrich Schwabe in the mid-1800s. -Sunspots are planet-sized islands of magnetism on the surface of the sun, and they are sources of solar flares, coronal mass ejections, and intense UV radiation. Plotting sunspot counts, Schwabe saw that peaks of solar activity were always followed by valleys of relative calm—a clockwork pattern that has held true for more than 200 years.
Atmospheric Aerosols
have a typical lifetime of one day to two weeks in the troposphere, and about one year in the stratosphere
Global change - its anthropogenic
human influences have warmed the climate at a rate that is unprecedented in the last 2000 years driven by emissions from human activities, with greenhouse gas warming partly masked by aerosol cooling
CO2 and water vapor are the 2 most
important greenhouse gases for absorption
Earth's surface
is 33°C warmer than it would be if had no atmosphere
Changes in Total Solar Irradiance (TSI) over the 11-year solar cycle
is about 0.24 W/m2 at the top of Earth's atmosphere, which is too small to have a significant influence on climate. -Two major indirect routes are potentially more effective -UV radiation can change 10-100% over the 11-yr solar cycle. That impacts ozone concentration, temperature and circulation in the stratosphere and eventually in the troposphere. -The second indirect effect, is the possible role of atmospheric ionization, resulting from GCR, in the production of new aerosol
atmosphere - components
is composed of gases and consists of several layers Nitrogen (N2) 78.1% Oxygen (O2) 20.1% Argon (Ar) 0.93% Water (H2O) 0.1 to 1% Carbon Dioxide (CO2) 0.035%
cloud feedback
is the coupling between cloudiness and temperature where a change in surface air temperature leads to a change in clouds, which could then amplify or diminish the initial temperature perturbation. As ice sheets melt, this could increase cloudiness with more water vapor in the atmosphere. Because low clouds reflect 1/3 of incoming solar radiation, there would be less heat absorption on Earth's surface Less heat absorbed at surface -> cooling -neg feedback if it's low -positive feedback if it's high --cirrus clouds--chem trails
Methane
lasts 9 years in atmosphere 30 times more potent than c02 -Colorless, odorless, flammable. -Formed under anaerobic conditions -when plants decay -bacteria - wetlands -bacteria - found in cows, sheep, goats, buffalo, termites, and camels. -Since 1750, methane has doubled, could double again by 2050. -Each year humans add 350-500 million tons of methane to atmosphere -Livestock, coal mining, drilling for oil and natural gas, rice cultivation, and landfills. -It's estimated to be over 30 times more potent in trapping GHG than CO2 over 100 years. -Its residence time in the atmosphere is about 10 years.
Trophosphere
layer of Earth's amosphere closest to Earth's surface (where weather takes place and where most pollution occurs) composed of gases and consists of several layers Contains about 75%-80% of earth's air and 99% of water vapor and aerosols 78% N, 20% O2, 0.01%-1% water vapor, 0.93% Ar and 0.035% CO2 and trace amounts of methane, ozone and nitrous oxide Circulation patterns in the troposphere determine the weather and climate and the distribution of water at the earth's surface
What is the effect of melting sea ice on albedo and climate change?
less reflectivity of earth surface and more absorption -however, with more clouds, there is more reflection and the oceans cant absorb as much as they would normally.
What's the role of the Earth's hot core in warming up the atmosphere?
little to no role compared to the sun Heat flow from the center of the Earth can be completely ignored when considering what determines the surface temperature of the Earth!
The Pinatubo Bears
n the summer of 1992 the ice on Hudson Bay melted almost a month later than normal. "That had a dramatic effect on the bears," Ian Stirling says. "They were bigger, they were heavier, they had more cubs, the cubs survived better. And the cubs that were born in that year, we call them the Pinatubo bears, because so many of them survived from that particular year class."
Greatest uncertainties:
net radiative properties of clouds role of anthropogenic aerosols response of the Greenland and Antarctic ice sheets & sea ice, future emissions, and human response to this threat.
What is the effect of deforestation on albedo and climate change?
potentially more reflection but more trees would help restore the balance. -
Galactic cosmic radiation-GCR
refers to sources of radiation in the form of high-energy particles originating outside the solar system. -Neutrons: produced by the impacts of GCR on atmosphere. -Aurorae: interaction of solar wind and the atmosphere. -Sunspots -Beryllium-10 is a cosmogenic isotope created in the atmosphere by galactic cosmic rays. It is measured in deposits of ice going back thousands of years.
Conduction, convection, and advection
requires molecules Conduction involves the direct movement of heat through an object. In convection and advection, a pocket of fluid such as air or water gets heated and then moves in currents.
Volcanoes
tend to exist along the edges of tectonic plates About 90% of all volcanoes exist within the Ring of Fire along the edges of the Pacific Ocean. Volcanoes are Active: show some level of activity and are likely to explode again Dormant: showing no current signs of exploding but are likely to become active at some point in the future Extinct: won't be active again. About 1,900 volcanoes on Earth are considered active.
What is the world scientific consensus?
that the Earth's climate is unequivocally warming, and that it is extremely likely (calc with at least 95% probability) that humans are causing most of it through activities that increase concentrations of atmospheric greenhouse gases
solar variability and climate-class slide
the Sun varies on varies several time scales Flares can erupt and peaks of energy can reach the earth in minutes Even small variations in the amount or distribution of energy received at Earth can have a major influence n climate when they persist for decades. However, no measurements indicate that solar output have contributed in a significant way to increase global mean temperature in the past 60 years. Locally, correlations between solar activity and variation in average weather have been found. Challenges: Establishing a unified record of solar output from present to prescientific past.
Earth's energy budget
the balance between the amount of energy coming in from the Sun and going back out into space minus 18 Celsius on average on earth if this was 100% true during our time its actually +15 celsius some lost to space, some emitted by atmosphere, some absorbed in clouds
Albedo
the fraction of solar radiation that is reflected or scattered back into space without any change in wavelength. the mean global albedo is about 30%. The albedo of different land surfaces varies greatly from 90% to less than 5%.
The Greenhouse Gases (GHG) effect:
the heat trapping effect of the atmosphere. The GHG effect is a natural process that increases the heating efficiency of the solar radiation. Today, the GHG concentrations in the global atmosphere is rising due to anthropogenic processes resulting in an "enhanced greenhouse effect," warmer temperatures, and global climate change.
Climatology
the study of Earth's climate and the factors that affect past, present, and future climatic changes need 30 years of data at least, 40 better
Ben franklin
was first to recognize the cooling effect of volcanoes The ice lasted longer and fog didn't go away Stratosphere- aerosols don't dissipate -He linked the abnormal weather over Europe in 1783-84 to the great Laki eruption in Iceland, which sent volcanic gases into the stratosphere and released over 100 million tons of sulfur dioxide over just a couple of months - As much as the world's industries release today in a year.
