Earth and atmospheric science
How did an increase in oxygen in the atmosphere effect life on earth?
Any organisms that couldn't tolerate the high levels of oxygen in the atmosphere died out, but some organisms evolved through natural selection to tolerate it, making use of the oxygen. The excess oxygen also made the ozone layer (O3) which blocked the harmful rays from the sun and enabled even more complex organisms to evolve, such as animals. Now due to the huge quantities of plants, there is virtually no CO2 left.
How did the oceans form?
As the earth began to cool, the water vapour in the atmosphere reduced as it condensed into oceans.
How does human activity increase global temperatures? (CO2)
Carbon dioxide in air is increasing: - The global population has risen rapidly in the last 150 years and more people means more energy is required for things such as lighting, heating, cooking and transport. - Lifestyles are also changing as more countries are industrialised and well off so the average energy demand per person is much higher |(more electric gadgets and more travel). The energy is mostly supported by fossil fuels which release CO2 into atmosphere More people means more land is needed for housing and services so trees are cut down which removes a carbon sink, so less carbon dioxide is removed from the atmosphere. CO2 is also produced by volcanoes erupting As consumption of fossil fuels increase, so does CO2 which means global temperatures increase because CO2 reflects and absorbs heat.
How does increasing greenhouse gases cause climate change?
Concentration of methane has increased lots during the recent years due to human activity. Methane is produced especially in many digestove tracts such as cattle goats and camel so more livestock farmed (for growing population) the more methane produced Although methane only increases in small amounts, it is a super effective greenhouse gas so it has large impacts The enhanced greemhouse effect caused has resulted in an increase in global temperatures - global warming. Global warming is a type of climate change that caan influence changes such as changing rainfall patterns and perhaps this could lead to severe flooding when the polar ice caps melt and sea levels rise.
What effect did the growth of primitive plants have over oxygen and carbon dioxide?
Green plants began to grow as they evolved over most of earth and as they photosynethesised, they removed CO2 and produced O2. this increased the overall levels of oxygen and decreased overall levels of carbon dioxide.
How did carbon dioxide levels decrease? How did nitrogen gas levels increase?
Lots of carbon dioxide form the early atmosphere dissolved in the oceans once they had formed. Nitrogen gas was released into the early atmosphere when ammonia reacted with oxygen and when denitrifying bacteria began to form. N2 isn't very reactive so once it was put into the atmosphere it was not broken down or reacted with so the amount continued to increase.
What is the chemical test for oxygen?
Place a glowing splint into gas and it should relight
What do some scientists believe about global warming?
Some believe tat is anthropogenic (caused by humans) but some believe that it is due to natural fluctuations (Milankovitch cycle) and that we do not currently have enough data to prove that global warming is caused by CO2.
What did Earth's early atmosphere contain?
The early atmosphere contained: - little or no oxygen - a large amount of carbon dioxide - water vapour - small amounts of other gases The carbon dioxide water vapour and other gases were released from volcanic eruptions.
How was the Earth's early atmosphere formed?
The earth's surface was originally moloten for many millions of years with no atmosphere, but when this began to cool and a thin crust formed, volcanoes erupted. The gases produced by volcanic activity (from inside the earth) formed the Earth's early atmosphere. The gases were mainly carbon dioxide but also contained steam methane and ammonia.
What is the greenhouse effect?
The sun has electromagnetic radiation and some of the EM radiation at most wavelengths pass through the atmosphere, but EM radiation with short wavelengths are often absorbed which warms our planet. The earth radiates (reflects) some of the heat radiation that was absorbed, but at longer wavelengths (such as infrared), and some of this is absorbed by greenhouse gases, or it is reflected back to earth by greenhouse gases. Part of it is re- emitted into space, but only the absorption and reflection of IR radiation by greenhouse gases keeps the earth warm and this is the greenhouse effect. Carbon dioxide water vapour and methane are greenhouse gases and are only abundant in small proportions. they are vital to keep the earth warm.
What is today's atmosphere composed of? How can we reduce greenhouse gas emissions?
Today's atmosphere: nitrogen (78%), oxygen (21%), argon (1%), and then trace amounts of greenhouse gases such as methane, water vapour and carbon dioxide (0.4%) Mitigation/adaptation: - the amounts of green house gases emitted can be reduced by making personal changes such as cycling rather than driving, turning heating down and installing solar panels to reduce fossil fuels. - On a large scale, the UK government have agreed to use 12.5% renewable sources in the international conference and this has replaced usage of fossil fuels. They could encourage the public and industries to become more energy efficient and even create financial incentives.
