CLIMATE CHANGE
Source: Pearson book unit 4. Climate change
4.4.1 Carbon dioxide and water are the most significant greenhouse gases
4.4.2 Other gases including methane and nitrogen oxides have less impact
4.4.3 The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.
4.4.4 The warmed Earth longer wavelength radiation (Heat)
4.4.5 Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere
4.4.6 Global temperature and climate patterns are influenced by concentrations of greenhouses gases
4.4.7 There is a correlation between rising atmospheric concentration of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures
4.4.8 Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.
4.4.1 Carbon dioxide and water are the most significant greenhouse gases
4.4.2 Other gases including methane and nitrogen oxides have less impact
4.4.3 The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.
4.4.4 The warmed Earth longer wavelength radiation (Heat)
4.4.5 Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere
4.4.6 Global temperature and climate patterns are influenced by concentrations of greenhouses gases
4.4.7 There is a correlation between rising atmospheric concentration of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures
4.4.8 Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.
the atmosphere
We live under the bottom of an ocean of air we call the atmosphere. It is so natural t us that we dont think about unless we are without it. The atmosphere play a vital role in regulating the temperature of Earth's surface.
The earth's surface has an average temperature of about 14C, fluctuations only very rare;y go lower than -80C or higher than 50C. In contrast the moon which is at the same distance from the sun that theearth had an average temperature from -150C to +120C depending on where the sunlight hits and this is because the moon doesnt have an atmosphere. It is estimated that if the earth had no atmosphere it will be 32C colder.
The earth's surface has an average temperature of about 14C, fluctuations only very rare;y go lower than -80C or higher than 50C. In contrast the moon which is at the same distance from the sun that theearth had an average temperature from -150C to +120C depending on where the sunlight hits and this is because the moon doesnt have an atmosphere. It is estimated that if the earth had no atmosphere it will be 32C colder.
the role of carbon dioxide and water vapour in the greenhouse effect
The consequence of the moon having little or no atmosphere is that it has no greenhouse effect. The greenhouse effect refers to a planet's ability to use its atmosphere to retain heat and keep warm even when no sunlight is hitting the surface. Greenhouses's walls and roof of a greenhouse are made of glass, and sunlight penetrates through the glass and warms up the plants inside. Sunlight itself which is made up short wavelength is not warm, the temperature of outer space between the Sun and the Earth is hundreds of bellow degrees freezing.
It is when the sunlight hits an objects that some of its energy is converted into heat.Heat energy has longer wavelengths than the energy of the sunlight. The objects inside radiate heat to the air inside the greenhouse, the glass of the greenhouse traps some of the heat to keep it warm inside. The result is that the inside is warmer than the outside which helps plants to grow when its cold outside.
Greenhouse gases such as water vapour and carbon dioxide in Earth's atmosphere can be thought of as the glass of a greenhouse. Greenhouse gases have the ability to absorb and radiate hear, when such gases are present they keep the atmosphere near Earth surface wrm , by absorbing heat from the warmed surface ad radiating it in all directions. In addition to carbon dioxide and water vapour, methane and nitrogen oxides alsoo contributes to the earth's greenhouse effect.
Increasing levels of the Greenhouse gases are causing the atmosphere to retain more and more heat.
It is when the sunlight hits an objects that some of its energy is converted into heat.Heat energy has longer wavelengths than the energy of the sunlight. The objects inside radiate heat to the air inside the greenhouse, the glass of the greenhouse traps some of the heat to keep it warm inside. The result is that the inside is warmer than the outside which helps plants to grow when its cold outside.
Greenhouse gases such as water vapour and carbon dioxide in Earth's atmosphere can be thought of as the glass of a greenhouse. Greenhouse gases have the ability to absorb and radiate hear, when such gases are present they keep the atmosphere near Earth surface wrm , by absorbing heat from the warmed surface ad radiating it in all directions. In addition to carbon dioxide and water vapour, methane and nitrogen oxides alsoo contributes to the earth's greenhouse effect.
Increasing levels of the Greenhouse gases are causing the atmosphere to retain more and more heat.
different gases, different impacts
Different gases in the atmosphere creates different impacts on the greenhouse effects on earth. There are two main factors that determine how much of an influence a gas will have on the greenhouse effect:
- The ability of the gas to absorb long-wave radiation (HEAT)
- The concentration of that gas in the atmosphere
greenhouse effect
•the greenhouse effect is a natural phenomenon transmission of incoming shorter-wave radiation through atmospheric gasses
•25% of short wavelength radiation that passes through the atmosphere is absorbed before it reaches the Earth’s surface
•75% of short wave radiation reaches the earth’s surface and converted to heat
•re-radiation of longer-wave radiation is reflected back to Earth by greenhouse gases
•25% of short wavelength radiation that passes through the atmosphere is absorbed before it reaches the Earth’s surface
•75% of short wave radiation reaches the earth’s surface and converted to heat
•re-radiation of longer-wave radiation is reflected back to Earth by greenhouse gases
•Natural greenhouse gases are vital to the survival of life on earth
•Carbon dioxide and water vapor are the most significant greenhouse gases
•Carbon dioxide
–Cell respiration
–fossil fuel combustion
–rain forest clearing & combustion
•Water vapor
–Formed by evaporation from oceans and transpiration in plants.
•Other gases including methane and nitrogen oxides have less impact
•Methane emissions
–agricultural rice paddy methanogen bacteria (emissions by intestinal methanogen bacteria in livestock)
–Extraction of fossil fuel
–Melting ice in polar regions
•Nitrogen oxides
–fossil fuel combustion
the warmed earth emits longer wavelengths radiation (HEAT)
When sunlight touches and object some of the light energy is absorbed and converted into heat energy also known as long-wave radiation. Most of the sunlight bounces off the surface and goes back to space. Only a small amount is converted into infrared to warm up the surface.
The ability of a surface to reflect light is called "ALBEDO", Light coloured objects such as ice and white sand have a high albedo, so very little light is absorbed and such objects do not heat a much as dark objects. Dark-colored objects like asphalt have low albedo and absorb lots of light and convert it into heat
The ability of a surface to reflect light is called "ALBEDO", Light coloured objects such as ice and white sand have a high albedo, so very little light is absorbed and such objects do not heat a much as dark objects. Dark-colored objects like asphalt have low albedo and absorb lots of light and convert it into heat
how greenhouses gases heat the atmosphere
If the earth had no atmosphere, at night we would have the same cold temperatures as the moon. But the reason that this doesn't happen is because of the greenhouse gases which absorbs heat coming from the surface. This gases can reradiate the heat in all directions, some of this heat will be lost in the space but some of the long wave radiation will be directed down to the surface, keeping it warm.The rest will stay in the atmosphere preventing it from getting extremely cold at night when no more sunlight is present. When the sun rises the next day all this process starts again.
During winter the days are shorter (the angles of the sunlight are less direct) and the earth surface cannot warm up as much as normal. This is why it is colder in winter. In summer days are longer and the sunlight hits the surface directly. Fortunately some gases in the atmosphere filter out some of the harmful radiation from the sun such as UV radiation. Because the atmosphere filters the sunlight not all of it reaches the surface, this is why the surface prevents the temperature to get as higher as the moon.
During winter the days are shorter (the angles of the sunlight are less direct) and the earth surface cannot warm up as much as normal. This is why it is colder in winter. In summer days are longer and the sunlight hits the surface directly. Fortunately some gases in the atmosphere filter out some of the harmful radiation from the sun such as UV radiation. Because the atmosphere filters the sunlight not all of it reaches the surface, this is why the surface prevents the temperature to get as higher as the moon.
global climate change is affected by greenhouse gases
Climate refers to the patterns of temperature and precipitation such as rainfall. Climate changes generally occur over thousands or millions of years. Proxis (came before thermometers) show data that 15000 years ago it was very cold, and earth was undergoing a glaciation or ice age. Ice ages were periods of significant change in climate that produced sheets of ice hundreds of metres thick in regions where today there are thriving cities. The last ice age ended about 10000 years ago and now we are in an interglacial period associated with warmer temperatures. It doesnt take much drop in temperature to produce glaciation, it is estimated that the last ice age was caused by a global average temp reduction of 5C.
Many factors are thought to contribute to global temperature changes over time like volcanic activity and radiation from the sun. But there appears to be a strong correlation between temperature increase and carbon dioxide increase. Knowing the properties of greenhouse gases we know that the increasing levels of CO2 will lead to warming of the atmosphere.
-Important: Closer inspection shows that the increase in temperature happens first and then the increase of CO2. This gap in time is partly because oceans warm up, they release carbon dioxide because gases dissolve less well in warm water than in cold water. A positive feedback leads to further increases in temperature over time.
Warm temperature->More CO2-> Warmer temperatures ->More CO2... and so on.
-Important: Closer inspection shows that the increase in temperature happens first and then the increase of CO2. This gap in time is partly because oceans warm up, they release carbon dioxide because gases dissolve less well in warm water than in cold water. A positive feedback leads to further increases in temperature over time.
Warm temperature->More CO2-> Warmer temperatures ->More CO2... and so on.
the industrial revolution
Ever since machines started to be use in the 1800s humans have produce more quantities of CO2 from factories, transport and other processes using fossil fuels. In addition burning forest to make ways for farmland and burning wood for cooking and heating has contributed also.
Over the decades human activities have produced enough CO2 considerably to raise the % of this gas in the atmosphere. Estimates suggest that eh levels if CO2 has increased by more than 35% compared to the pre-industrial revolution.
Over the decades human activities have produced enough CO2 considerably to raise the % of this gas in the atmosphere. Estimates suggest that eh levels if CO2 has increased by more than 35% compared to the pre-industrial revolution.
production of the gases
CO2: Cars, lorries, trains, airplanes, deforestations, heating homes by burning fossils fuels, high meat diets, purchasing goods that have to be transported long distances and more.
Methane: High meat diets, methane is produces by anaerobic organisms presents in the guts of animals. Cattle are responsible for producing large amounts of methane.
NOx: burning fuels, using organic and commercial fertilizers, industrial processes.
Methane: High meat diets, methane is produces by anaerobic organisms presents in the guts of animals. Cattle are responsible for producing large amounts of methane.
NOx: burning fuels, using organic and commercial fertilizers, industrial processes.
temperature rise and coral reefs
Coral reefs are sensitive to 3 things water temperature, water acidity and the depth of water, and because of the climate change the oceans have changed a lot producing:
•Ocean acidification leads to death of coral polyps and algae
•CO2 reacts with water to form carbonic acid, which dissociates into hydrogen and hydrogen carbonate ions.
•Reef building corals need carbonate ions to build their skeletons.
As a result coral reefs die and interrupts the food chain causing many of the organisms that live there to seek food and shelter elsewhere.
•Ocean acidification leads to death of coral polyps and algae
•CO2 reacts with water to form carbonic acid, which dissociates into hydrogen and hydrogen carbonate ions.
•Reef building corals need carbonate ions to build their skeletons.
As a result coral reefs die and interrupts the food chain causing many of the organisms that live there to seek food and shelter elsewhere.