Science Changes in Climate and Human Activities and Climate Change Quiz


Terms in this set (...)

Weather forecast
A prediction about changes in upcoming weather (could influence how you plan your day)
Long term changes in climate:
(Rather than being like weather forecasts) Happen more slowly and may not be apparent for years, but the consequences can be great
What is the principle scientists follow when studying ancient climates?
If plants or animals today need certain conditions to live, then similar plants and animals in the past also required those conditions. (Greenland is now covered by an ice cap, but 80 million years ago it had a moist climate. Fossils of magnolia and palm trees found provide evidence for the climate change, because magnolias and palm trees are native to warm, moist climates, like florida.
What are three sources of information about ancient climates
Pollen, Tree Rings, and Ice Cores
Pollen (as information about ancient climates)
Each type of plant has a particular type of pollen and some lake bottoms have accumulated thick layers of mud and plant material, including this pollen, over thousands of years. Scientists drill down into these layers and bring up samples to examine the, and they can tell what type of plant lived their.
Tree rings (as information about ancient climates)
Each summer, a tree grows a new layer of wood just under its bark, which form rings. Wide rings indicate a good growing season that was long or wet. Narrow rings indicate a dry year or short growing period. Scientists study the patterns of thick or thin tree rings to
see if previous years were wet or dry and warm or cool.
Ice cores (as information about ancient climates)
By drilling three kilometers down into the ice (almost eight times longer than the Empire State Building) scientists remove ice cores which have a layer for each year like tree rings. Scientists study these layers to find out about earth's climate record and can also analyze what's in the layers of ice, such as pollen or dust.
Why do climates change (natural factors)?
Possible explanations for major climate changes include movement of the continents, variations in the position of earth relative to the sun, major volcanic eruptions, and changes in the sun's energy output.
Earth's Position (causing climate change)
The angle of earth's axis and the shape of earth's orbit affect earth's climate. Earth travels in elliptical orbit around the sun, but shape of this elipse varies over a period around 100,000 years. More elliptical - less sunlight reaches earth during the year (and this change causes earth to experience an ice age.) More circular - earth warms. The angle earth's axis tilts and the direction of the axis also change over time, affecting the severity of ice ages. These changes cause repeating 100,000 year cycles of ice ages interrupted by warm periods.
Ice Age (causing climate change)
A period of glacial advance where huge sheets of ice called continental glaciers covered large parts of earth's surface, which transform the land by carving grooves in rocks and depositing piles of sediment, and moving huge boulders hundreds of kilometers. There there were 20 major ice ages in the last two million years. Brief, warm periods called interglacial occur between long cold ice ages. (Last ice age ended 10,000 years ago)
Movement of Continents (causing climate change)
200 million years ago much of the land on earth was part of a single continent called Pangaea, where most of the continents were far from their present positions. Continents that are now in polar zones were once near the equator, which explains how tropical plants such as magnolias and palm trees could have once been native to Greenland. These movements of continents over time changed the locations of land and sea and affected the global patterns of winds and ocean currents, which slowly change climates. As the continents continue to move, their climates will continue to change.
Solid particles or liquid drops in gas from major volcanic eruptions that can stay in the upper atmosphere for months or years and (with ash) reflect away incoming solar radiation, lowering temperatures.
Light Given off by the Sun
Short term changes in climate have been linked to the amount of light given off by the sun which changes in a regular 11 year cycle (and can also change over hundreds of years). The number of sunspots increases when the sun gives off more light.
Dark, cooler regions on the sun, which increase when the sun gives off more light and can be used to measure solar output over the past 400 years
How are Human Activities Affecting Earth's Climate?
Humans change the air, land, and water of Earth's surface faster than most geological processes and are causing a major change in the temperature of earth's atmosphere.
Greenhouse gases
Water vapor, carbon dioxide, and methane, that absorb the heat leaving earth's surface
Levels of Greenhouse gases (human impact)
Many human activities are increasing the level of greenhouse gases in the atmosphere and producing changes in climate worldwide which is causing global temperatures to rise.
Carbon Dioxide
One of the most abundant greenhouse gases, which humans release billions of tons of into the atmosphere each year, mostly by burning fossil fuels.
Fossil fuels
Energy rich substances formed from the remains of organisms. Humans burn fossil fuels such as coal, natural gas, and gasoline to generate electricity, heat homes, and power cars.
Human activities and livestock (who emit methane) increase the amount of the greenhouse gas methane. As large numbers of cattle raised for food production rise, more methane is released (almost doubling amount of methane in past century)
Temperature Increase
Over the last 120 years the temperature of the troposphere has increased by about 0.7 degrees Celsius. This gradual increase in the temperature of earth's atmosphere is called global warming. The increasing levels of greenhouse gases are causing global temps to rise quicker than before.
Climate Models
Complex computer programs predicting global temperatures may rise over the next hundred years and use data to predict the temperature, precipitation, and other atmospheric conditions, which are being worked on by scientists to become more specific about how warming will affect particular regions
Melting glaciers and rising sea levels (global warming)
Scientists have observed glaciers retreating in many mountain ranges over the last century and there is evidence it is happening worldwide. Temps in part of antártica have risen 6 degrees over 50 years, causing ice sheets to collapse. Because of the melting glaciers, sea levels have risen 122 meters and will continue to rise.
Droughts and desertification (global warming)
Regions can get very warm and dry as global temps rise, leading to droughts, like the one in southwestern U.S. The droughts cause lands to become deserts (desertification), which leads to food shortages.
The effects of global warming
The effects of global warming include melting glaciers, rising sea levels, droughts, desertification, changes to the biosphere, and regional changes in temperatures.
Global warming is part of a larger set of changes to Earth's climate that together are called;
Climate Change
Global warming
The gradual increase in the temperature of earth's atmosphere
Changes to the biosphere (global warming)
Species that can't adapt to to new locations may become extinct because of global climate change making them find new locations. (Species that can adapt to warmer climates will)
Regional Changes in temperature (global warming)
Global temp changes affect regions differently. During the 20th century global temps increased by an average of less than one degree while some got warmer by five degrees and others cooler. In some areas temperature changes have led to longer growing seasons.
Solutions for limiting global warming and climate change include
Finding clean, renewable sources of energy, being more energy efficient, and removing carbon from fossil fuel emissions
Clean Energy Sources
Energy sources which release very small amounts of greenhouse gases, such as solar, wind, hydro electrical, geothermal, nuclear, and tidal energy.
Earth receives as much energy from the sun as humans use in
a year
Efficient Energy
One of the best ways to reduce global warming is using more efficient technologies, like clean energy power plants that can power electric and hydrogen fuel cell cars and steam from power plants that factories can run on.
Carbon Capture
The process of removing carbon dioxide from the exhaust from fossil fuels and burying it under ground - fewer greenhouse gasses are released (more expensive and more energy
Energy efficient habits:
Turning off lights when you leave a room or using public transportation