Human Effects on Atmosphere and Relation to Global Warming

Human Actions Affecting Atmosphere

• Demand for goods produced in factories-production often has CO2 byproduct

• Aerosols (tiny solid or liquid particles suspended in air) produced by transportation, industry, agriculture-alters precipitation patterns, can contribute to holes in ozone layer

• Chlorofluorocarbons, still used in air conditioning units-contribute to holes in ozone layer

• Agriculture-raising large amounts of animals produced excess methane

Global Warming• Industrialization of countries and making

decisions on a personal level that increase air pollution is the suggested cause for an increase in the Earth’s average temperature, or global warming.

• What is most directly responsible for increased global temperatures?• Increased CO2 emissions

Ways We Increase Carbon In Atmosphere

• Burning fossil fuels, such as coal, oil, gasoline, natural gas– Reasons for burning of fossil fuels• Transportation• Produce electricity• Heating homes and buildings• Manufacturing goods, such as shoes and clothing• Production of paper• Agriculture

The Greenhouse Effect

• The greenhouse effect is a natural heating of the Earth’s surface in which greenhouse gases, primarily carbon dioxide, but also includes methane, water vapor, and ozone, absorb the Sun’s energy radiated from the Earth and keeps Earth’s surface temperature warm.

• Not entirely, without the greenhouse effect, conditions on Earth would be too cold to support life.

• However, the increased measure of greenhouse gases being released into the air over the past few hundred years has intensified the greenhouse effect, causing warming than normal surface temperatures.

• Our planet would be cold, like Mars, which has a very thin atmosphere and surface temperatures that can drop to -90⁰C

• But too much can be a bad thing – our planet would look like Venus – too hot and greenhouse effect gone wild

Is the Greenhouse Effect a Bad Thing?

What’s the difference between “global warming” and

“climate change”?

GLOBAL WARMING is the increase of the

Earth’s average surface temperature

CLIMATE CHANGE is change in regional

climate characteristics, such as rainfall, humidity, and severe weather events

What contributes to climate change?

Natural causes:*Volcanic eruptions*Sunspots*El Nino/La Nina*Seasonal Fluctuations

Human causes:*Burning fossil fuels*Deforestation (both linked to industrialization)*Urbanization

• Volcanic eruptions – work to cause more global cooling than global warming

• WHY? During eruptions, sulfur combines with water vapor in stratosphere. These particles can absorb huge amounts of energy, limiting the energy dispersed to the troposphere.

Volcanic Eruptions

During higher occurrence of sunspots on Sun’s surface, greater radiation is emitted. This radiation is absorbed by Earth’s atmosphere, relatively intensifying the greenhouse effect.

Sunspots

• Cause of El Nino-trade winds moving west along the equator diminish. As a result, warm ocean currents move east, ceasing the upwelling of cold, deep ocean water that would typically occur along the coast of South America.

• Cause of La Nina-the opposite of El Nino’s cause. Trade winds strengthen as they move west. These stronger winds more so move warmer waters away from the South American coast, allowing more upwelling of colder, nutrient rich ocean waters.

El Nino/La Nina

El Nino/La Nina – How long does it last?

• A strong El Niño can last a year or more before conditions return to normal. We usually get one every three to seven years.

• Effects of El Nino-increased rainfall in US and Peru, causes flooding; drought conditions in Australia, Africa, and Indonesia. Warm water limits nutrient supply in ocean waters, some fisheries suffer along North and South American western coastlines.

• La Niña-opposite of El Nino-decreased precipitation rates in US and Peru; higher precipitations rates in Australia, Africa, and Indonesia; Colder water brings excess nutrient supply, fisheries do well.

Effects of El Nino/La Nina

Seasonal Fluctuations

• Higher CO2 concentration fall/winter season due to lack of vegetation absorbing CO2.

• Lower CO2 concentration during spring/summer

What causes climate change – human causes?

Human Causes of Climate Change

Fossil fuels (coal, oil, natural gas)

Carbon Dioxide (CO2)

• For photosynthesis to occur, plants must take in carbon dioxide and release oxygen

• Deforestation leads to the mass removal of trees and therefore reduces the rate of photosynthesis, which leaves more carbon dioxide remaining in the atmosphere

• Deforestation also involves machinery that burns fossil fuels, adding to carbon dioxide in atmosphere.

Deforestation

Burning Fossil Fuels

• Industrialization has increased burning of fossil fuels, resulting in increased carbon dioxide emission, worsening the greenhouse effect

Urbanization-Create Heat Islands• As urban areas develop,

infrastructure replaces open land and vegetation. Surfaces that were once permeable and moist become impermeable and dry.

Increased population leads to increased emission of greenhouse gases. These changes cause urban regions to become warmer than their rural surroundings, forming an "island" of higher temperatures in the landscape.

Effects of Global WarmingIncreased Temperature

Habitat Damage and

Species Affected

Ocean Acidification

Rising Sea Level

Rising Sea LevelsThe loss of large areas of ice on the surface could accelerate global warming because less of the sun's energy would be reflected away from Earth to begin with. An immediate result of melting glaciers would be a rise in sea levels. Initially, the rise in sea level would only be an inch or two. Even a modest rise in sea levels could cause flooding problems for low-lying coastal areas. However, if the West Antarctic Ice Sheet were to melt and collapse into the sea, it would push seal levels up 10 meters (more than 32 feet), and many coastal areas would completely disappear beneath the ocean.

Portage Glacier

1914 2004

• Alaska

Photos: NOAA Photo Collection and Gary Braasch – WorldViewOfGlobalWarming.org

Melting Glaciers = More Earthquakes?

In a new study, NASA and United States Geological Survey (USGS) scientists found that retreating glaciers in southern Alaska may be opening the way for future earthquakes. The study examined the likelihood of increased earthquake activity in southern Alaska as a result of rapidly melting glaciers. As glaciers melt they lighten the load on the Earth's crust. Tectonic plates, that are mobile pieces of the Earth's crust, can then move more freely.

Patagonian ice fields

Increased Temperatures

Poor communities are most directly dependent for their livelihoods on a stable and hospitable climate. Many areas, including southern Australia and parts of Africa, are seeing longer and more frequent droughts as the climate gets hotter.

Hot, dry summers are fuelling massive blazes across the high-latitude forests of Russia and North America.

Increased Temperatures

Methane Hydrates, locked within the seabed at the bottom of deep oceans could become unstable as the sea temperature rises. Should that happen, global warming could go well beyond current projections leading to runaway climate change. It is believed that methane hydrates may have been involved in some of the most intense warming periods in Earth’s history.

Increased Temperatures

As the Siberian permafrost melts Methane trapped within the frozen bog escapes into the atmosphere causing further increases in GHG concentrations. Permafrost has warmed by up to 2°c since the 1980s.

Habitat Damage and Species Affected

Climate change could kill more than a third of the world’s plant and animal species by 2050. As the world warms species are losing habitat and unable to adapt to the rapidly changing conditions. Some species may become less/more abundant, disrupting the food chain.

Habitat Damage and Species Affected

Melting icebergs and glaciers means less ice for polar bears to breed and reproduce on. It also means more swimming for the bears, which requires more energy and therefore more food for the bear.

Ocean Acidification

1. Up to one half of the carbon dioxide (CO2) released by burning fossil fuels over the past 200 years has been absorbed by the world's oceans

2. Absorbed CO2 in seawater (H2O) forms carbonic acid (H2CO3), lowering the water's pH level and making it more acidic

3. This raises the hydrogen ion concentration in the water, and limits organisms' access to carbonate ions, which are needed to form hard parts

4. Populations of these organisms are limited, disrupting food chains

The pH of the world's oceans is not consistent across the globe. Researchers believe that areas with relatively low pH (the purple areas on the map above), such as the eastern Pacific, could be the result of the upwelling of deeper, colder, CO2-richer waters.

Ocean Acidification

Effects of Ocean AcidificationDecreased amount of coral reefs, plankton, and invertebrates

*Warm water coral reefs - Evidence suggests that the calcification rates of these corals will be reduced by up to 60%; a reduction of this magnitude could adversely affect reef structures, as growth depends on corals' ability to build faster than the skeleton is eroded. Weaker structures are likely to be prone to greater degrees of erosion from storms and heavy wave action.

*Cold-water corals - cold-water corals can provide vital habitat for several commercially important fish species. Forecasts suggest that about 70% of the corals could find themselves under threat by the end of the century.

*Plankton - These tiny organisms play an important role in the marine food chain. Several groups of plankton produce calcium carbonate, and could see their distribution curtailed by ocean acidification.

*Invertebrates - the main impact is expected to be thin or deformed shells. Juveniles have been shown to be more susceptible than adults to limited carbonate ions, which could have long-term consequences as far as viable populations are concerned.

Ways to Mitigate Human Influence on Climate Change-Local level

• Support renewable energy initiatives• Decrease demand for goods with high carbon

footprint-buy locally• Improve insulation, use energy efficient bulbs,

install skylights in homes• Recycle materials• Turn off lights when not in use• Shop with a canvas bag, limiting use of plastic• Wash clothes in cold water instead of hot

Ways to Mitigate Human Influence on climate change-government scale

• Urban planning-public transportation, close proximity of housing to town centers

• Increase forested land• Utilize natural gas, produces 30% less CO2

when burned• Develop solar radiation management

techniques