Atmosphere and Climate Change. Climate Weather is the conditions that occur in the atmosphere are...

Atmosphere and Climate ChangeAtmosphere and Climate Change

ClimateClimate

WeatherWeather is the conditions that occur in the is the conditions that occur in the atmosphere are over a atmosphere are over a short period of timeshort period of time..

ClimateClimate is how the atmosphere "behaves" is how the atmosphere "behaves" over relatively over relatively long periods of timelong periods of time. .

When we talk about climate change, we talk When we talk about climate change, we talk about changes in about changes in long-term averageslong-term averages of of daily weather. daily weather.

Past Climate Change Past Climate Change

The Earth's climate has changed throughout The Earth's climate has changed throughout history. history.

From From glacial periodsglacial periods (or "ice ages") where (or "ice ages") where ice covered significant portions of the Earth ice covered significant portions of the Earth to to interglacial periodsinterglacial periods where ice retreated to where ice retreated to the poles or melted entirely - the climate has the poles or melted entirely - the climate has continuously changed. continuously changed.

Past Climate Change Past Climate Change

Scientists have been able to piece together Scientists have been able to piece together a picture of the Earth's climate dating back a picture of the Earth's climate dating back decades to millions of years ago by decades to millions of years ago by analyzing a number of analyzing a number of substitute, or "proxy," substitute, or "proxy," measures of climate. measures of climate.

Past Climate ChangePast Climate Change

Examples of “proxy” measures include:Examples of “proxy” measures include:– ice coresice cores– boreholesboreholes– tree ringstree rings– glacier lengths glacier lengths – pollen remains pollen remains – ocean sediments ocean sediments – studying changes in the Earth's orbit around the studying changes in the Earth's orbit around the

sun.sun.


Causes of Change Prior to the Industrial Causes of Change Prior to the Industrial Era (pre-1780)Era (pre-1780)– Changes in the Earth's orbitChanges in the Earth's orbit – Changes in the sun's intensityChanges in the sun's intensity – Volcanic eruptionsVolcanic eruptions – Changes in ocean currentsChanges in ocean currents


The Last 2,000 YearsThe Last 2,000 Years– During the last 2,000 years, the climate has During the last 2,000 years, the climate has

been been relatively stablerelatively stable. . – Scientists have identified Scientists have identified three departuresthree departures from from

this stability, known as the Medieval Warm this stability, known as the Medieval Warm Period, the Little Ice Age and the Industrial EraPeriod, the Little Ice Age and the Industrial Era


Prior to the Industrial Era, the Medieval Prior to the Industrial Era, the Medieval Warm Period and Little Ice Age had defined Warm Period and Little Ice Age had defined the the upper and lower boundariesupper and lower boundaries of the of the climate's recent natural variability and are a climate's recent natural variability and are a reflection of changes in climate drivers (the reflection of changes in climate drivers (the sun's variability and volcanic activitysun's variability and volcanic activity) and ) and the climate's internal variability (referring to the climate's internal variability (referring to random changes in the circulation of the random changes in the circulation of the atmosphere and oceansatmosphere and oceans). ).

Recent Climate Change Recent Climate Change

Since the Industrial Revolution (around Since the Industrial Revolution (around 1750), human activities have substantially 1750), human activities have substantially added to the amount of heat-trapping added to the amount of heat-trapping greenhouse gases in thegreenhouse gases in the atmosphereatmosphere. .

The burning of The burning of fossil fuelsfossil fuels and and biomassbiomass (living matter such as vegetation) has also (living matter such as vegetation) has also resulted in emissions of resulted in emissions of aerosolsaerosols that that absorb and emit heat, and reflect light.absorb and emit heat, and reflect light.

Factors That Determine ClimateFactors That Determine Climate

Elevation or Altitude Prevailing global wind patterns Latitude and angles of the suns rays Topography Distance from the equator Ocean circulation patterns Volcanic activity

The Ozone LayerThe Ozone Layer

"The ozone layer" "The ozone layer" refers to the ozone refers to the ozone within stratosphere, within stratosphere, where over where over 90%90% of the of the earth's ozone resides. earth's ozone resides.


The ozone layer The ozone layer absorbsabsorbs a portion of the radiation a portion of the radiation from the sun, preventing it from reaching the from the sun, preventing it from reaching the planet's surface. planet's surface.

Most importantly, it absorbs the portion of Most importantly, it absorbs the portion of ultraviolet lightultraviolet light called UVB. called UVB.

UVB has been linked to many harmful effects, UVB has been linked to many harmful effects, including various types of including various types of skin cancerskin cancer, cataracts, , cataracts, and harm to some crops, certain materials, and and harm to some crops, certain materials, and some forms of marine life. some forms of marine life.


The ozone layer absorbs 97-99% of the The ozone layer absorbs 97-99% of the sun's high frequency ultraviolet light , light sun's high frequency ultraviolet light , light which is potentially damaging to life on which is potentially damaging to life on earth. earth.

Every Every 1% decrease1% decrease in the earths ozone in the earths ozone shield is projected to increases the amount shield is projected to increases the amount of UV light exposure to the lower of UV light exposure to the lower atmosphere by 2%. atmosphere by 2%.

Chemicals That Cause Ozone Chemicals That Cause Ozone Depletion Depletion

Chlorofluorocarbons (CFCs)Chlorofluorocarbons (CFCs) – used as refrigerants, solvents, foam blowing used as refrigerants, solvents, foam blowing

agents, fire extinguishing agents agents, fire extinguishing agents – CFCs have atmospheric lifetimes long enough CFCs have atmospheric lifetimes long enough

to allow them to be transported by to allow them to be transported by windswinds into into the stratosphere. the stratosphere.

– Because they release Because they release chlorine or brominechlorine or bromine when when they break down, they damage the protective they break down, they damage the protective ozone layer. ozone layer.

The Ozone HoleThe Ozone Hole

CFCs, HCFCs, carbon tetrachloride, methyl CFCs, HCFCs, carbon tetrachloride, methyl chloroform, and other gases release chlorine chloroform, and other gases release chlorine atoms, and halons and methyl bromide release atoms, and halons and methyl bromide release bromine atoms bromine atoms

It is these atoms that actually It is these atoms that actually destroy ozonedestroy ozone..

It is estimated that one chlorine atom can destroy It is estimated that one chlorine atom can destroy over over 100,000 100,000 ozone molecules before it is ozone molecules before it is removed from the stratosphere.removed from the stratosphere.

Protecting the Ozone LayerProtecting the Ozone Layer

Montreal ProtocolMontreal Protocol on Substances That Deplete on Substances That Deplete the Ozone Layerthe Ozone Layer – International treatyInternational treaty designed to protect the ozone layer designed to protect the ozone layer

by phasing out the production of a number of by phasing out the production of a number of substances believed to be responsible for ozone substances believed to be responsible for ozone depletion. depletion.

– Since the Montreal Protocol came into effect, the Since the Montreal Protocol came into effect, the atmospheric concentrations of the most important atmospheric concentrations of the most important chlorofluorocarbons and related chlorinated chlorofluorocarbons and related chlorinated hydrocarbons have either hydrocarbons have either leveled off or decreasedleveled off or decreased

Global WarmingGlobal Warming

Global warmingGlobal warming is the is the increase in the increase in the average temperature average temperature of Earth's near-of Earth's near-surface air and surface air and oceans since the mid-oceans since the mid-20th century and its 20th century and its projected projected continuation.continuation.

The Greenhouse EffectThe Greenhouse Effect

Energy from the Sun drives the Earth's Energy from the Sun drives the Earth's weather and climateweather and climate. .

The Earth The Earth absorbs energyabsorbs energy from the Sun, from the Sun, and also and also radiates energyradiates energy back into space. back into space.

However, much of this energy going back to However, much of this energy going back to space is absorbed by space is absorbed by “greenhouse” gases“greenhouse” gases in in the atmosphere the atmosphere

The Greenhouse EffectThe Greenhouse Effect

Because the atmosphere then Because the atmosphere then radiates most radiates most of this energy backof this energy back to the Earth’s surface, to the Earth’s surface, our planet is warmer than it would be if the our planet is warmer than it would be if the atmosphere did not contain these gases.atmosphere did not contain these gases.

Without this natural "greenhouse effect," Without this natural "greenhouse effect," temperatures would be abouttemperatures would be about 60ºF 60ºF lower lower than they are now, and life as we know it than they are now, and life as we know it today would not be possible. today would not be possible.

Greenhouse GasesGreenhouse Gases

Carbon dioxide Carbon dioxide Water vaporWater vapor Methane Methane Nitrous oxide Nitrous oxide Fluorinated gases Fluorinated gases

– Hydrofluorocarbons, perfluorocarbons, and Hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride sulfur hexafluoride

Carbon DioxideCarbon Dioxide

Carbon dioxide enters the atmosphere through the Carbon dioxide enters the atmosphere through the burning of fossil fuelsburning of fossil fuels (oil, natural gas, and coal), (oil, natural gas, and coal), solid waste, trees and wood products, and also as solid waste, trees and wood products, and also as a result of other chemical reactions (e.g., a result of other chemical reactions (e.g., manufacture of cement). manufacture of cement).

Carbon dioxide is also removed from the Carbon dioxide is also removed from the atmosphere (or “sequestered”) when it is absorbed atmosphere (or “sequestered”) when it is absorbed by plants as part of the biological by plants as part of the biological carbon cyclecarbon cycle. .

Carbon Dioxide (non-energy related) Carbon Dioxide (non-energy related) EmissionsEmissions

Cement manufactureCement manufacture– calcium carbonate is heated to produce limecalcium carbonate is heated to produce lime– In 1998, the United States manufactured an In 1998, the United States manufactured an

estimated estimated 85.5 million85.5 million metric tons of cement, metric tons of cement, resulting in the direct release of carbon dioxide resulting in the direct release of carbon dioxide containing about 10.6 million metric tons of containing about 10.6 million metric tons of carbon into the atmosphere. carbon into the atmosphere.

Measuring Carbon DioxideMeasuring Carbon Dioxide

The rise of carbon The rise of carbon dioxide gas in our dioxide gas in our atmosphere has been atmosphere has been measured continuously measured continuously since since 19581958..

Methane EmissionsMethane Emissions

Sources include energy production and consumption Sources include energy production and consumption such as:such as:– coal mining coal mining – natural gas systemsnatural gas systems

Waste managementWaste management– landfill gaslandfill gas

AgricultureAgriculture– manure managementmanure management– cattle (enteric fermentation)cattle (enteric fermentation)– rice cultivationrice cultivation

Nitrous Oxide (N2O) EmissionsNitrous Oxide (N2O) Emissions

Agricultural soil managementAgricultural soil management– nitrogen fertilizationnitrogen fertilization

Mobile sourcesMobile sources Acidic acid productionAcidic acid production

– used to make nylonused to make nylon

Expected Consequences of GHG Expected Consequences of GHG Concentration IncreasesConcentration Increases

TemperatureTemperature:: Global temperatures are Global temperatures are rising. rising.

Observations collected over the last century Observations collected over the last century suggest that the average land surface suggest that the average land surface temperature has risen temperature has risen 0.45-0.6°C (0.8-0.45-0.6°C (0.8-1.0°F)1.0°F) in the last century. in the last century.


Rising Sea LevelRising Sea Level – Hotter temperatures mean ice -- glaciers, sea Hotter temperatures mean ice -- glaciers, sea

ice and polar ice sheets -- is melting, increasing ice and polar ice sheets -- is melting, increasing the amount of water in the world's seas and the amount of water in the world's seas and oceans. oceans.


Shrinking GlaciersShrinking Glaciers – In the span of a century, glaciers in Montana's In the span of a century, glaciers in Montana's

Glacier National Park have deteriorated from Glacier National Park have deteriorated from 150 to just 35150 to just 35. .

– And the Himalayan glaciers that feed the And the Himalayan glaciers that feed the Ganges River, which supplies drinking and Ganges River, which supplies drinking and irrigation water to irrigation water to 500 million people500 million people, are , are reportedly shrinking by 40 yards (37 meters) reportedly shrinking by 40 yards (37 meters) each year.each year.

Montana's Glacier National Park Montana's Glacier National Park


Heat WavesHeat Waves – Extreme heat waves are happening two to four Extreme heat waves are happening two to four

times more often now, steadily rising over the times more often now, steadily rising over the last 50 to 100 years, and are projected to be last 50 to 100 years, and are projected to be 100 times more likely over the next 40 years.100 times more likely over the next 40 years.


Storms and FloodsStorms and Floods– Warm waters give Warm waters give

hurricanes their hurricanes their strength, and scientists strength, and scientists are correlating the are correlating the increase in ocean and increase in ocean and atmospheric atmospheric temperatures to the rate temperatures to the rate of violent storms. of violent storms.


DroughtDrought – As the climate warms, experts estimate drought As the climate warms, experts estimate drought

conditions may increase by at least 66 percent conditions may increase by at least 66 percent [source: [source: Scientific AmericanScientific American]. ].

– An increase in drought conditions leads quickly An increase in drought conditions leads quickly to a shrinking water supply and a decrease in to a shrinking water supply and a decrease in quality agricultural conditions. quality agricultural conditions.

http://howstuffworks.com/framed.htm?parent=worst-effects-global-warming.htm&url=http://www.sciam.com/article.cfm?id=state-of-the-science-beyond-the-worst-climate-change-case


DiseaseDisease– Warmer temperatures Warmer temperatures

along with associated along with associated floods and droughts are floods and droughts are encouraging worldwide encouraging worldwide health threats by health threats by creating an environmentcreating an environment where mosquitoes, where mosquitoes, ticks, mice and other ticks, mice and other disease-carrying disease-carrying creatures thrive. creatures thrive.


Economic Consequences Economic Consequences – Consumers face rising Consumers face rising food and energy costsfood and energy costs

along with increased insurance premiums for along with increased insurance premiums for health and home. health and home.

– Governments suffer the consequences of Governments suffer the consequences of diminished tourismdiminished tourism and industrial profits, and industrial profits, soaring energy, food and water demands, soaring energy, food and water demands, disaster cleanup and border tensions. disaster cleanup and border tensions.


Loss of Biodiversity Loss of Biodiversity – As many as As many as 30 percent of plant and animal 30 percent of plant and animal

speciesspecies alive today risk extinction by 2050 if alive today risk extinction by 2050 if average temperatures rise more than 2 to 11.5 average temperatures rise more than 2 to 11.5 degrees F (1.1 to 6.4 degrees C) [sources: degrees F (1.1 to 6.4 degrees C) [sources: EPA, Scientific American]. EPA, Scientific American].

– Such extinctions will be due to Such extinctions will be due to loss of habitatloss of habitat through desertification, deforestation and ocean through desertification, deforestation and ocean warming, as well as the inability to adapt to warming, as well as the inability to adapt to climate warming. climate warming.


Destruction of Ecosystems Destruction of Ecosystems – Changing climatic conditions and dramatic Changing climatic conditions and dramatic

increases in carbon dioxide will put our increases in carbon dioxide will put our ecosystems to the test, threatening supplies of ecosystems to the test, threatening supplies of fresh waterfresh water, clean air, fuel and energy , clean air, fuel and energy resources, food, resources, food, medicinemedicine and other matters we and other matters we depend upon not just for our lifestyles but for depend upon not just for our lifestyles but for our survival.our survival.

Coral BleachingCoral Bleaching

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