Chapter 15 - Climate Change - Environmental Science (BIO 1127) - SU 2020 - CSCC - Dr. Javadi

Pacific Decadal Oscillation (PDO)

A large pool of warm water that moves north and south in the Pacific Ocean every 30 years or so and has large effects on North America's climate. This affects the size of salmon harvests in Alaska and the Pacific Northwest.

greenhouse effect

A natural phenomena where the atmosphere transmits sunlight while trapping heat. This process supports life as we know it.

The financial expense of global warming

- At present, reducing greenhouse gas emissions would cost 0.5% of world GDP according to Stern report. (IPCC report says less than that.) - If we delay, it could cost as much as 20% of world GDP. - Energy production will need to be 80% decarbonized by 2050 to stabilize climate. - Those in richer countries will be able to blunt the effects of climate change. - Those in poorer countries will suffer the most; at least 200 million people will become refugees of floods or victims of drought.

Observations of Climate Change

- Average global temperature climbed 0.6°C (1°F) in last century. - 19 of 20 warmest years in the past 150 yrs have occurred since 1980.Poles are warming fastest (4°C, 7°F over past 50 years). - Permafrost is melting in Alaska and Canada and houses, pipelines are being damaged and trees are being toppled. - Arctic Sea ice is half as thick as it was 30 years ago, and the ocean area covered by ice has decreased by 1 million km 2 in 30 yr. - Polar bears are dying as they attempt to find pack ice (which is declining) on which to hunt. - Antarctic ice shelves are disappearing. - Penguins declined 50% in that last 50 yrs. - Glaciers are retreating all over the world. - The oceans are absorbing and storing more heat. - Sea level has risen 15 to 20 cm in last century.

Effects of Global Warming and Climate Change

- People will experience more extreme weather including droughts, floods, heat waves, and hurricanes. - These could have disastrous economic and human costs. - Estimates published in 2009 project a sea level rise of 0.6 meter. - This could flood low-lying coastal cities like New Orleans, Miami, Boston, New York, London, and Mumbai. - Melting ice and rising sea levels - Flooding and spread of disease - Threat of species extinction - Extreme weather conditions - Forest fires

The effects of ocean currents on weather

- Warm and cold ocean currents strongly influence climate conditions on land. - As surface water moves, deep water wells up to replace it, causing deeper ocean currents. -Ocean circulation also driven by differences in water density due to temperature and saltiness of water - Currents can shift abruptly.

Why does it rain?

-Air cools as it rises, and water condenses as air cools. -Pressure decreases as air rises, causing cooling. -Condensation nuclei (tiny particles) must also be present to have precipitation.

4 Steps For Combating Climate Change

1) Implement emissions trading 2) Technology sharing with less developed countries 3) Reducing deforestation 4) Helping poorer countries respond to climate change

cold front

A boundary formed when cooler air pushes away warmer air. - Cold air is more dense, tends to hug ground and pushes warm air up. -The warm air is cooled -Triggers strong thunderstorms

warm front

A boundary formed when warm air slides over cooler air. - Warm air is less dense and slides over cool air - A long wedge-shaped band of clouds is formed - Can bring days of drizzle.

Historical Climate Changes

A historical climate change that had destabilizing effects on human populations was the Little Ice Age that began in the 1400's. Temperatures dropped, crops failed, fish migrations changed and shipping lanes were blocked with ice.

El Niño / The El Niño Southern Oscillation (ENSO)

A naturally occurring (ocean-atmospheric) climate event where warm surface waters in Pacific Ocean move back and forth between Indonesia and South America. - Most years, the pool is held in western Pacific by steady equatorial trade winds. - Surface waters driven westward by trade winds allow upwelling of cold, nutrient rich waters off west coast of South America benefiting fisheries. - Every three to five years the Indonesian low collapses and the mass of warm surface water surges back east.

Paris Climate Agreement (2015)

A pledge by over 150 countries to significantly decrease their carbon emissions by 2030. The 195 countries in attendance at the meeting agreed on a number of major points. Holding the global average temperature increase to well below 2°C (above pre-industrial levels) is necessary. Below 1.5°C should be the target. Reduction plans submitted thus far are not sufficient to keep warming below 2°C, so plans must be revised every five years.

monsoon

A seasonal reversal of wind patterns caused by differential heating and cooling rates of oceans and continents. Most prevalent in subtropical and tropical areas. - Tilt of Earth's axis changes location where the Sun is most intense over the course of the year. Places where the Sun shines most directly have evaporation and convection currents which bring thunderstorms. - Seasonal rains support tropical forests and fill great rivers such as Ganges and Amazon. - Supports life, but flooding can also take it away. - Failure of monsoon rains brings drought, starvation, and death to both livestock and people in the Sahel desert margin of Africa.

hurricane

A severe storm that develops over tropical oceans and whose strong winds of more than 120 km/h spiral in toward the intensely low-pressure storm center

typhoon

A tropical storm, like a hurricane, that occurs in the Western Pacific.

Intergovernmental Panel on Climate Change (IPCC)

An international group of scientists and governmental representatives from 130 countries formed to review the scientific evidence for climate change. The 2013-2014 report stated that there is a 99% probability that the observed climate changes are the result of human activities. The report projects warming of 1 to 6°C by 2100 with the best estimate being 2 to 4°C (3 to 8°F). For perspective, there has only been a 5°C rise since the last ice age 20,000 years ago.

North Atlantic Oscillation (NAO)

Another oscillation (similar to the Pacific Decadal Oscillation) which occurs between Canada and Europe.

Coriolis effect

As air warms at the equator, rises, and moves northward, it sinks and rises in several intermediate bands, forming circulation cells. This curving pattern results from the fact that the earth rotates in an eastward direction as winds move above it. Surface flows do not move straight north and south, but are deflected due to the ________ effect. Winds and currents appear to move clockwise in Northern Hemisphere and counterclockwise in the Southern Hemisphere.

What Can You Do?

Burning fossil fuels produces about half our greenhouse gas emission, and transportation accounts for about half of our fossil fuel consumption. Driving less, choosing efficient vehicles, carpooling, and other conservation measures are among our most important personal choices in the effort to control global warming. [See image for other conservation measures]

Kyoto Protocol (1997)

Called on nations to roll back carbon dioxide, methane, and nitrous oxide emissions about 5% below 1990 levels by 2012. - Sets different limits for different countries, depending on prior output - China and India were both exempt from this agreement. - Many countries ratified the Protocol. - The legislatures of both Australia and the U.S. declined to ratify the agreement.

anthropogenic climate change

Climate change which is caused by humans, either directly or indirectly.

ice cores

Cylinders of ice drilled out from glaciers and polar ice sheets that have revolutionized our understanding of climate history. - Air bubbles trapped in ice can be analyzed for atmospheric composition. - Reveals information about past atmospheric conditions. - We can reconstruct past temperature patterns. - Vostok ice core gives us a record back 420,000 years.

ENSO Effects on North America

During an El Niño year, the northern jet stream pulls moist air from the Pacific over the U.S. Intense storms and heavy rains from California to the Midwestern states. During intervening La Niña years, hot, dry weather is often present. Resulting high sea surface temperatures cause hurricanes to be more violent.

Much of solar energy absorbed by the Earth is used to evaporate water. Energy is stored in water vapor as _______ heat. When water vapor condenses, heat energy is released. Heat and water move from warmer areas near the equator toward cooler areas at poles. Heat redistribution prevents extreme temperature fluctuation.

Energy is stored in water vapor as latent heat

What creates local weather?

Frontal systems

Why Do We Still Debate Climate Evidence?

Funding given to groups promoting climate denial in popular media, blogs, and political lobbying. Sources include oil and gas industries and anonymous contributions to the Donor's Trust.

greenhouse gases

Gases in the atmosphere, especially carbon dioxide, water vapor, nitrous oxides, methane, and other substances that retain heat.

jet streams

Hurricane force winds at the top of the troposphere. - Follow an undulating path - Affect weather patterns

CO2 increases

Initial measurements showed carbon dioxide levels increasing at 0.5% per year since data collection began. Fossil-fuel burning is the major human caused source of carbon dioxide. - Levels have risen from 315 ppm in 1958 to 397 ppm in 2011. - CO2 is the Most Important Greenhouse Gas. - Carbon Dioxide - emissions have doubled from 1970 to 2010. - If a computer model can accurately predict past climate, this is an indication of its effectiveness at predicting future climate.

carbon trading

Legal limits on emissions are set and countries that want to emit more must purchase emissions credits from others. - This approach is favored under Kyoto. - A global market for trading carbon emissions has already developed. - In 2006, 700 million tons of carbon credits were exchanged with a value of $3.5 billion. - This market may grow to $500 billion a year by 2050. - Some large businesses like BP America, Dupont, and GE are for this approach if the rules are clear and fairly applied.

climate

Long-term patterns of temperature and precipitation.

carbon neutral

Making no net release of carbon dioxide to the atmosphere, especially through offsetting emissions by planting trees.

recent climate change

Many scientists believe that anthropogenic climate change is the most important environmental issue of our time. - The earliest data came from an observatory on Mauna Loa volcano in 1957. - Currently carbon dioxide levels are rising at over 2 ppm per year. - Levels have risen from 315 ppm in 1958 to over 400 ppm in 2017. - If this trend continues, we could double atmospheric CO2 levels within a century.

Should We Focus on Methane Instead of CO2?

Methane is a more powerful absorber of heat energy than carbon dioxide. Reducing methane emissions from landfills, rice paddies, oil wells, and coal mines could reduce warming. Reducing the number of ruminants (E.g. cattle, sheep, goats, buffalo, deer, elk, giraffes and camels) could help also.

Mesosphere

Middle Layer of Earth's atmosphere where the temperature diminishes again.

Most solar energy reaching the Earth is _________ radiation. Energy re-emitted by the earth is mainly _________ radiation.

Most solar energy reaching the Earth is near infrared radiation. Energy re-emitted by the earth is mainly far infrared radiation (long wavelength, heat). Longer wavelengths are absorbed in the lower atmosphere, trapping heat close to the earth's surface.

Milankovitch Cycles

Periodic shifts in Earth's orbit and tilt which change distribution and intensity of sunlight.

La Niña episodes

Periods of below-average sea surface temperatures across the east-central Equatorial Pacific. La Niña impacts tend to be opposite those of El Niño impacts. During a La Niña year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.

weather

Physical conditions in the atmosphere (humidity, temperature, air pressure, wind, and precipitation) over short time scales. Short-lived, local patterns; temperature and precipitation due to circulation of the troposphere.

stabilization wedges

Policy options for reducing greenhouse gas emissions using existing technologies. Each wedge represents a cumulative reduction of the equivalent of 1 billion tons of carbon over the next 50 years. By utilizing Wedge Analysis the problem of climate stabilization can be broken down into smaller, bite-sized pieces. - To stabilize carbon emissions we would need to cut 7 GT (gigatons) over the next 50 years. - Doubling vehicle efficiency, and halving the miles we drive would save up to 1.5 GT. - Installing energy efficient appliances, lighting, and building insulation could save another 2 GT. - Capturing and storing carbon emissions from power plants and gas wells could save another GT.

The phenomenon causing the greenhouse effect is that _______________ in the lower atmosphere selectively absorb(s) reradiated ____________ radiation. A. Ozone; visible light B. Carbon dioxide, methane, and other gases; infrared (heat) C. Hydrocarbons; very short wavelength D. Carbon dioxide; ultraviolet

The phenomenon causing the greenhouse effect is that Carbon dioxide, methane, and other gases in the lower atmosphere selectively absorb(s) reradiated infrared (heat) radiation.

methane sources and energy absorption

Ruminants (E.g. cattle, sheep, goats, buffalo, deer, elk, giraffes and camels) and rice paddies are sources. Absorbs more energy than CO2.

Which one has the greatest albedo: Sand, dense clouds, fresh snow, water?

Snow.

tornadoes

Swirling funnel clouds over land. Generated by "supercell" frontal systems where strong dry cold fronts collide with warm humid air. Greater air temperature differences in the spring, thus more tornadoes.

carbon capture and storage

The process of capturing waste CO2, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally underground.

albedo

The ability of a surface to reflect light.

Stratosphere

The second-lowest layer of Earth's atmosphere. - From tropopause up to about 50 km -Has almost no water vapor, but 1000X more ozone than the troposphere - Ozone absorbs ultraviolet light, which warms the upper part of this layer. - Ozone protects all life on Earth since UV radiation damages living tissues. -Ozone is being depleted by pollutants including Freon and bromine.

Tropopause

The boundary that limits mixing between the troposphere and upper zones as air ceases to rise.

circulation cells

The global circulation can be described as the world-wide system of winds by which the necessary transport of heat from tropical to polar latitudes is accomplished. In each hemisphere there are three cells (Hadley cell, Ferrel cell and Polar cell) in which air circulates through the entire depth of the troposphere.

Troposphere

The lowest layer of Earth's atmosphere that is immediately adjacent to the earth's surface. - Ranges in depth from 18 km over the equator to 8 km over the poles. - Convection currents redistribute heat and moisture around the globe. - Air temperature drops rapidly with increasing distance from the earth.

wind

The movement of air from high to low pressure areas.

Thermosphere

The uppermost layer of the atmosphere, in which temperature increases as altitude increases. - Begins at 80 km - Ionized gases and high temperatures - The lower part of this layer has ions which are struck by high energy radiation resulting in the Aurora borealis (northern lights)

convection currents

The upward movement of warm air and the downward movement of cool air. - Releasing latent heat causes air to rise, cool, and lose more water vapor as precipitation. - Warm air close to equator vs. cold air at poles also produces pressure differences that cause weather. - Air near the surface warms and becomes less dense than the air above it; rises above cool air creating vertical convection currents. -Low pressure - air is rising -High pressure - air is sinking

Ocean / Atmosphere Cycle

There are decades long oscillations in the oceans and atmosphere. The ocean and the atmosphere have regular patterns of flow or currents, but these may shift from time to time. Winds and rains may change as a consequence of these shifts.

Nitrous Oxide sources and energy absorption

Vehicle engines and agriculture processes are major sources. Highly effective at capturing heat energy.

cyclonic storms

When water vapor is abundant the latent heat released by condensation intensifies convection currents and draws up more warm air and water vapor. Storm cell will exist as long as temperature differences exist.

four zones of the atmosphere

troposphere, stratosphere, mesosphere, thermosphere

Air near the earth's surface warms and becomes less dense than the air above it; rises above cool air creating _______________________.

vertical convection currents