Weather KQ2 Flashcards
What is the greenhouse effect?
It is a natural process in which the gases in the Earth’s atmosphere trap longwave radiation emitted from the earth’s surface, warming the atmosphere.
Name a few greenhouse gases.
Water vapour, carbon dioxide, methane, nitrous oxide, ozone and halocarbons such as chlorofluorocarbons.
How does the increase in solar output lead to higher global temperatures?
The sun emits varying amounts of solar radiation due to changes in its magnetic field. The magnetic activity of the sun has a cycle that lasts about 11 years which peaks with increased solar activity. Increase in magnetic activity results in an increase in solar radiation. With higher solar radiation, earth’s temperatures will increase. For example, peak solar activity in 2000 lead to higher global temperatures by 0.1-0.2 °C
How do volcanic eruptions lead to lower atmospheric temperatures?
Dust particles from eruptions form condensation nuclei, creating more cloud cover. Dust and ash also reflect away incoming solar radiation. Sulphur dioxide reacts with water to form sulfur-based particles which also reflect solar radiation. Gradual reduction in the amount of sunlight reaching the earth’s surface leads to a temporary cooling of the earth for months or years. For example, Mount Pinatubo eruption lowered temperatures by as much as 0.6°C for as long as 2 years.
How does the burning of fossil fuels contribute to the greenhouse gases in the atmosphere?
Fossil fuels are formed from decomposition of dead organic matter over millions of years, for example petroleum, coal, and natural gases. Fossil fuels are burnt to generate energy for industry, transport, agriculture, and urban areas. It contains high carbon content and releases huge amounts of carbon dioxide when burnt. Fossil fuels provide 80% of the world’s energy but are also the highest contributor to greenhouse gases, mostly from industry, with emissions contributing above 75% of the global greenhouse gas emissions.
How does deforestation increase the concentration of greenhouse gases in the atmosphere?
The trees are cut down for wood to make paper or building materials. Trees are also removed to clear land for mining, agriculture or building roads. Thus, there are fewer trees to absorb carbon dioxide. Also, carbon in soil reacts with oxygen to produce carbon dioxide, aided by higher temperatures when soil is exposed to sunlight. Deforestation accounts for 10-15% of total greenhouse gas emissions.
How does agriculture contribute to greenhouse gas emissions?
Farm machinery runs on fossil fuels, which releases carbon dioxide. Bacteria living in wet rice fields produce methane. As the amount of agriculture increases, the use of fertilizers also increase. Nitrous oxide is released when nitrogen-based fertilizers in the soil break down. Cattle farming releases methane into the atmosphere as gases are released from the digestive systems of cattle. For example, in Argentina, 30% of the country’s greenhouse gas emissions come from cattle farming.
How do greenhouse gases warm the earth? (5 Step drawing)
Incoming shortwave radiation from the sun passes through the greenhouse gases found in the atmosphere. Some shortwave radiation is reflected by the earth and the atmosphere. Most shortwave radiation is absorbed by the earth’s surface which then heats up as a result. The warmed surface of the earth emits longwave radiation to the atmosphere. Greenhouse gases absorb longwave radiation, warming the atmosphere.
What is the impact of sea level rise?
Sea level rise is the increase in the mean height of the sea’s surface between high tide and low tide relative to land. Sea level rise occurs because higher atmospheric temperatures causes water to expand. Higher temperatures also cause glaciers to melt, adding meltwater to the sea. Low lying coastal areas are lost to flooding by rising levels and many people may have to be relocated. Low-lying countries such as Maldives and Palau are at risk.
What are the impact of more frequent extreme weather events?
Extreme weather events are severe and rare weather phenomena such as heat waves and floods that result in significant economic losses and the loss of lives. Due to climate change, these events are occurring more frequently and at greater intensities. For example, the number of weather events has been increasing since 1980 to 2005 from around 40 events a year to around 70 events a year.
What is the impact of the spread of infectious insect-borne diseases?
Increased rainfall and temperatures are favourable conditions for mosquitoes to breed. As temperate countries get warmer, the area that mosquitoes are able to breed in increases and they are now able to breed at higher latitudes and at higher altitude. Many more areas are faced with the burden of these diseases and for longer periods of time. For example, Dengue fever was reported for the first time in cool climate areas such as Nepal in 2004.
What is the impact of climate change on the intensity of food production?
Higher temperatures have led to longer growing seasons and increased food production for some temperate regions. However, increasing temperatures will result in decreases in food production in tropical counties due to increased droughts and floods. For example, India is expected to experience a decrease of 25-35% in crop production and Ethiopia a decrease between 20-30%.
What is an international response to climate change?
Kyoto protocol was set up with the aim of reducing levels of greenhouse gases (GHG) in the atmosphere and was drawn up in 1997 and came into force in 2005. Participating countries were given targets to reduce GHG emissions. Developed countries had to reduce their GHG emissions by at least 5% below 1990 levels and they had to help less developed countries reduce their GHG emissions. Many countries have met or exceeded their targets such as Austria and Finland and the Kyoto protocol was successful in encouraging sustainable development by allowing developed countries to meet their GHG emission reductions by taking emission-reduction projects in less developed countries. However, some countries such as Denmark, Sweden and UK did not achieve their targets.
Evaluate the Singapore Green Plan 2012.
The Singapore Green Plan 2012 was launched to reduce greenhouse gas emissions by using natural gas as an energy source. Launched by the Ministry of Environment in 2002 and it aimed to generate 60% of Singapore’s energy needs using natural gas by 2012. This is because natural gas is a cleaner form of energy as it does not produce smoke. As a result, 79% of Singapore’s electricity was generated from natural gas by 2010. However, Natural gas requires complex treatment plants to process and pipelines to transport. These pipelines have high maintenance costs because they need to be laid underground and checked regularly for leakage.
Evaluate the Green Mark Scheme.
The Green Mark Scheme was launched by the Building and Construction Authority (BCA) in 2005. Buildings were to be evaluated and certified according to how energy-efficient and environmentally friendly they are and it aims to encourage more new ‘green’ buildings which are more energy-efficient and use less energy to provide the same service. Existing ‘green’ buildings such as Plaza by the Park and National Library Building, have reported energy savings of 15-35% compared to conventional buildings which results in cuts in GHG emissions by reducing the use of fossil fuels to generate electricity. However, it costs more to build ‘green’ buildings as ‘green’ materials may be more expensive which may discourage construction companies and developers in Singapore.
