Climate Flashcards
(70 cards)
1
Q
Definition: Weather
A
Refers to the state of the atmosphere at a particular time.
2
Q
Definition: Climate
A
Refers to the average state of the atmosphere at a particular place over a long period of time, typically 30 years or more.
3
Q
Climographs: Tropical Equatorial Climate
A
- Generally high temperatures all year round, about 27°C.
- Small temperature range of about 2-3°C.
- High precipitation of more than 2000mm.
- Precipitation falls evenly throughout the year.
4
Q
Climographs: Tropical Monsoon Climate
A
- Generally warm all year round, about 25°C.
- Moderate temperature range of about 3-4°C.
- High precipitation of more than 1500mm.
- Distinct wet and dry seasons.
5
Q
Climographs: Cool Temperate Climate
A
- Four seasons: spring, summer, autumn, and winter.
- Large annual temperature range of about 21°C.
- Low annual precipitation between 300-900mm.
- Precipitation falls evenly throughout the year.
6
Q
Variations in Temperature: Over Time
A
- Mainly due to the Earth’s rotation on its axis.
- One complete rotation around the axis takes about 24 hours.
- As the Earth rotates, the side facing the sun experiences day and receives solar radiation, leading to higher temperatures. The opposite side experiences night, resulting in varying temperatures over the day.
7
Q
Variations in Temperature: Over a Year
A
- Air temperature varies due to the Earth’s revolution around the sun.
- The Earth’s axis is tilted at an angle of 23.5°.
8
Q
June: Northern vs. Southern Hemisphere
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- Northern Hemisphere: Leans more towards the sun, receives more direct solar radiation, and experiences higher temperatures.
- Southern Hemisphere: Leans away from the sun, receives less direct solar radiation, and experiences lower temperatures.
9
Q
December: Northern vs. Southern Hemisphere
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- Northern Hemisphere: Leans away from the sun, receives less direct solar radiation, and experiences lower temperatures.
- Southern Hemisphere: Leans more towards the sun, receives more direct solar radiation, and experiences higher temperatures.
10
Q
March and September: Northern vs. Southern Hemisphere
A
- Neither hemisphere leans towards the sun, hence both experience moderate temperatures.
- Northern Hemisphere: Experiences spring in March and autumn in September.
- Southern Hemisphere: Experiences autumn in March and spring in September
11
Q
Temperature Variations: Latitude
A
- The higher the latitude, the lower the temperatures, and vice versa.
- Due to the Earth’s spherical shape, the angle at which the sun’s rays strike the Earth’s surface (solar angle) varies.
- At high latitude, the solar angle is smaller, solar radiation is weaker and is spread over a larger area, resulting in lower temperatures.
12
Q
Temperature Variations: Altitude
A
- At a given location, temperatures are lower at higher altitudes.
- At higher altitudes, air is less dense, air pressure is lower, and there are fewer air molecules to absorb and radiate heat, leading to lower temperatures.
- Solar energy heats the Earth’s surface directly via shortwave radiation. The Earth emits heat & warms up the atmosphere via longwave radiation. At lower altitudes, more exposure to longwave radiation results in higher temperatures.
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13
Q
Temperature Variations: Type of Surface
A
- Dark surfaces (e.g., asphalt and forests): Absorb more solar radiation and radiate more heat, leading to higher temperatures.
- Light-colored surfaces: Generally reflect more solar radiation and radiate less heat, leading to lower temperatures.
14
Q
Variations of Precipitation: Types of Soil
A
- Infiltration rates and groundwater flows are faster in soil which has larger pores than in soil with smaller pores.
- Larger pores allow more water to infiltrate, allowing the water to move more quickly.
15
Q
Variations of Precipitation: Extent of Built-Up Areas
A
- Infiltration rates are lower in built-up areas where ground surfaces are covered in concrete, which has tiny pores.
- The speed of surface runoff is higher on smoother ground surfaces, such as roads and pavements in built-up areas, due to fewer obstructions and lesser friction.
16
Q
Variations of Precipitation: Presence of Natural Vegetation
A
- Infiltration rates and groundwater flow are faster where there is natural vegetation.
- The roots of plants loosen the soil, creating more open spaces for water to pass through.
- The speed of surface runoff is lower on vegetated areas as the stems and roots of grasses and plants act as barriers and increase the surface roughness.
17
Q
Formation of Rain: Convectional Rain
A
- During the day, the land is heated up by the Sun.
- Heat from the sun is absorbed by the land, causing the air above it to rise.
- The warm air rises, cools, and condenses on condensation nuclei at dew point temperature to form clouds.
- Water droplets in the clouds collide and coalesce, and when they become large and heavy enough, they fall to the ground as rain.
18
Q
Formation of Rain: Relief Rain (Windward Side)
A
- Moist winds pick up moisture over the sea and push the moist air up the windward side of a mountain.
- The rising moist air cools and condenses on condensation nuclei at dew point temperature. Clouds are formed.
- Water droplets in the clouds collide and coalesce, and when they become large and heavy enough, they fall to the ground as rain on the windward side.
19
Q
Formation of Rain: Relief Rain (Leeward Side)
A
- Since most of the moisture has fallen on the windward side, the leeward side experiences dry descending air, leading to lower rainfall and often creating arid conditions.
20
Q
Winds: Pressure Gradient and Wind Speed
A
Weak Pressure Gradient: Smaller difference in pressure between two areas leads to slower wind speeds. (Vice versa for strong pressure gradient).
21
Q
Winds: Effect of Friction on Wind Speed
A
- Moving air interacts with variations in the Earth’s topography, experiencing friction, which reduces wind speed.
- The effect of frictional drag is greatest where there is uneven relief and rough surfaces on land, such as valleys and mountains.
22
Q
Localised Wind: Sea Breeze
A
- During the day, heat from the Sun is absorbed by both the land and the sea through shortwave radiation.
- The land gains heat quickly, causing the air above it to warm, become less dense, and rise, forming an area of lower pressure over the land.
- The sea and the air above it gain heat slowly, remaining cooler, denser, and forming an area of higher pressure over the sea.
- Air moves from the area of higher pressure over the sea to the area of lower pressure over the land, forming a sea breeze.
23
Q
Localised Wind: Land Breeze
A
- The opposite applies for a land breeze, where at night the land cools faster, creating higher pressure over land and lower pressure over the sea, causing air to move from land to sea.
24
Q
Regional Winds: Northeast Monsoon
A
- Occurs during winter in the Northern Hemisphere.
- Central Asia and the Indian subcontinent experience winter, where air sinks to form an area of high pressure.
- Australia experiences summer, where air rises to form an area of low pressure.
- Air moves from the region of high pressure in the Northern Hemisphere to the region of low pressure in the Southern Hemisphere.
- In the Northern Hemisphere, winds get deflected to the right, forming the Northeast Monsoon, which is experienced by countries like Singapore and Malaysia.
25
Monsoon Rains
* The Northeast Monsoon is dry and cool as it picks up little moisture from Central Asia, leading to little rain in India.
* As the winds blow over the South China Sea, they pick up moisture, bringing heavy rain to areas like Singapore.
* When the wind crosses into the Southern Hemisphere, it deflects to the left and continues to pick up moisture over the Indian Ocean, bringing rain to countries like Indonesia and Australia.
26
Natural Causes of Climate Change: Earth's Orbit and Tilt
* Orbit Shape Progression: The Earth's orbit stretches from circular to an elliptical shape and back again.
* Cycle: 100,000 years.
* Tilt Progression: The Earth's axis varies between 21.5 degrees and 24.5 degrees.
* Cycle: 41,000 years.
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Impact on Earth's Temperature: Orbit Shape
* When the Earth’s orbit is the most elliptical, the Earth travels in a more oval shape.
* More radiation reaches Earth at the planet’s closest approach to the Sun than at the farthest departure from the Sun.
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Impact on Earth's Temperature: Axis Tilt
* When the tilt decreases, the hemisphere leans further away from the Sun, leading to warmer winters and cooler summers.
* This enables the build-up of large ice sheets in higher latitudes, cooling the Earth.
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Variations in Solar Output
* Varying solar radiation emitted by the Sun due to changes in its magnetic field.
* Dynamic 11-year cycle of magnetic activity associated with high and low global temperatures.
* During intensive solar magnetic activity periods, sunspots increase, leading to increased solar radiation.
* Sunspots are cooler areas on the Sun, but their vicinity radiates more energy to compensate for the coolness.
* **Example:** In 2001, the number of sunspots observed was 170, indicating high solar activity.
30
Volcanic Eruptions and Climate Change
* Cause global cooling because ejected materials (sulfur-based particles) along with ash and dust reflect heat back into space, lowering Earth’s temperatures.
* Global cooling is short-term and ceases after the dust and ash settle.
* Can cause global warming due to greenhouse gases (GHGs) released by the volcano.
* Example: Mount Pinatubo, Philippines, 1991, released abundant sulfur dioxide, forming sulfur-based particles that reflected solar energy back into space.
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Greenhouse Effect: Definition
The process by which the greenhouse gases in the Earth’s atmosphere trap longwave radiation.
32
Enhanced Greenhouse Effect
* Occurs due to increased anthropogenic activities that have led to an increase in CO2, resulting in more heat being excessively trapped in the atmosphere.
33
Deforestation and Atmospheric CO2
* Deforestation: Clearing of forests for timber, mining, and agricultural activities leads to an increase in atmospheric CO2.
1. **Fewer trees** mean less CO2 absorption because trees absorb CO2 and release oxygen through photosynthesis.
2. **Burning forests** to clear land emits CO2. Exposed carbon-rich soil from decayed leaves and animals reacts with oxygen through oxidation, producing more CO2.
* Occurs greatly in South America, Southeast Asia, and Africa.
* Between 2000 & 2010, yearly forest loss was 52,000 sq km.
34
Urbanisation and Greenhouse Gas Emissions
* Urbanisation: Cities consume about 78% of the world’s energy and contribute significantly to GHG emissions.
* Urban population increase leads to higher energy consumption for lighting, heating, cooling, and cooking, increasing GHG emissions.
* Construction of infrastructure (e.g., roads, rails, bridges) and the use of automobiles contribute to the greenhouse effect.
35
Changing Land Use: Agriculture
* Agriculture: Increased demand for food leads to more farming, contributing to GHG emissions.
* Paddy farming emits methane in rice fields.
* Tractors powered by fossil fuels release CO2.
* Fertilizers release nitrous oxide when fields are plowed, and rain splashes on carbon-rich soil.
* Rapidly decaying matter (e.g., dead leaves and manure) in rice fields releases methane.
* Cattle farming emits methane from livestock raised for meat.
36
Industrialization and CO2 Emissions
* Industrialization: Involves the manufacture of goods, requiring the burning of fossil fuels to generate electricity in factories and run automobiles for transporting raw materials and goods, emitting CO2.
37
Increase in Atmospheric and Ocean Surface Temperature
* Temperatures increase due to industrialization, leading to higher levels of greenhouse gases (GHGs) in the environment.
* Most heat trapped by GHGs is absorbed by the oceans, resulting in an increase in the average ocean temperatures.
38
Changes to Ocean Circulation
* Ocean water moves globally in large-scale movements, known as ocean circulation:
1. Warm surface water moves from the equator to the poles due to winds.
2. The water then cools, becomes denser, and sinks.
3. Cold water moves towards the equator, forming deep ocean currents.
4. The cool water eventually rises back to the surface.
* Climate change is expected to slow down global ocean circulation as rising surface temperatures make water less dense, reducing its sinking at the poles
39
Changes in Precipitation on Land
**Climate change is altering precipitation patterns:**
* Wet regions are expected to become wetter with increased precipitation, leading to more frequent excessive rainfall.
* Dry regions are expected to get drier, leading to more frequent droughts.
40
Threats to Coral Reefs
* Coral reefs are highly fragile and vulnerable to changes in temperature.
* Increase in ocean temperature causes algae to leave corals, leading to coral bleaching.
* Bleached corals are more likely to die, affecting species that depend on them for food and habitat, thus disrupting the entire ecosystem.
41
Ocean Acidification
* Oceans act as natural carbon sinks due to the presence of phytoplankton.
* Increased CO2 emissions lead to oceans absorbing excessive CO2, forming carbonic acid, making oceans more acidic.
* Acidic oceans reduce the availability of carbonate ions, essential for aquatic organisms like corals, mussels, and oysters to form their skeletons and shells.
* Coral reefs are eroding faster than new corals can form, negatively affecting species dependent on them.**
42
Disruptions to Marine Food Webs
* Ocean circulation transports heat and nutrients between surface and deep waters.
* Slowing down of ocean circulation reduces the sinking of water at the poles, leading to less mixing of warm surface water with cooler, nutrient-rich deep waters.
* This causes a drop in phytoplankton, affecting species that feed on them, such as fish and whales, disrupting the entire marine ecosystem.
43
Threats to Terrestrial Flora and Fauna
**Geographic distribution of species is changing:**
* Terrestrial species are migrating towards higher latitudes and altitudes where temperatures are cooler.
* As species migrate, the composition of terrestrial ecosystems changes, disrupting existing food webs and forming new communities.
* Mountain species may face extinction if they cannot find suitable habitats at higher altitudes.
44
Impacts of Droughts on Flora and Fauna
* Plants are vulnerable to droughts as they cannot move to find water, leading to withering, death, and increased susceptibility to diseases and insect attacks.
* Animals are forced to move in search of water, leading to potential habitat loss and competition.
45
Impact of Excessive Rainfall on Flora and Fauna
* Intense rainfall can lead to floods, destroying habitats and causing terrestrial species to drown and die.
46
Differing Extent of Climate Change Impacts on People
**The impact varies based on:**
* Different climate conditions (temperatures/precipitation).
* The level of socioeconomic factors due to differences in economic development.
47
What is an example of an increase in sea surface temperatures over the last century?
Sea surface temperatures have warmed by slightly over 1°C.
48
How can changes in ocean circulation affect weather patterns in Europe?
Changes can disrupt the Gulf Stream, impacting weather in Europe.
49
What impact did rising sea temperatures have on the Great Barrier Reef in 2016 and 2017?
Up to two-thirds of corals died in the northern section of the reef.
50
How much are coral reefs expected to decline if ocean temperatures increase by 1.5°C?
Coral reefs are expected to decline by up to 90%.
51
What change in bird species distribution has been observed in North America over the past four decades?
About 170 species of birds have expanded their range northwards by 50 km on average.
52
How are wallabies in Australia adapting to climate change?
Wallabies are migrating to higher altitudes, impacting herbfields by overgrazing.
53
What was the impact of droughts in California between 2012 and 2016?
Droughts contributed to the death of 102 million forest trees.
54
How can intense rainfall from climate change affect homes and agricultural land?
Increased flooding can destroy homes and agricultural land, as seen in the 2017 hurricanes affecting the Caribbean and parts of the U.S.
55
Heat Waves: Definition
* A heat wave is a prolonged period of excessively hot weather that is abnormal, usually lasting several days or longer.
* Temperatures during heat waves can exceed 40°C.
* Climate change increases the likelihood and severity of heat waves by raising overall temperatures.
56
Heat Waves: Impact on Humans
* People may suffer from heatstroke, breathing difficulties, and death due to extreme temperatures.
* High temperatures can cause dehydration, leading to widespread crop failures.
* Crop failures affect food supply and security.
57
Heat Waves: European Heat Wave
* The 2003 European heat wave lasted two weeks.
* Approximately 70,000 people died due to extreme heat.
* The heat wave severely affected the harvest of crops like wheat, leading to food shortages.
* The price of bread increased significantly, making food less affordable
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Droughts: Definition
* A drought occurs when an area or region experiences a prolonged lack of precipitation (rain or snow).
* Extended periods without precipitation lead to water shortages.
* Climate change increases evaporation rates, which depletes water sources and dries out soil and vegetation.
* Droughts are more likely in already dry climates, such as the subtropics and mid-latitudes.
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Droughts: Impact on Humans
* Shortages of clean water can lead to dehydration.
* Crop failures due to lack of water can result in hunger and malnutrition.
* Droughts may displace populations; by 2030, up to 700 million people may be displaced due to drought.
61
Droughts: Afghanistan Drought (2018-2019)
* The drought affected more than two-thirds of Afghanistan.
* Over ten million people suffered from a lack of food and many were displaced.
62
Wildfires: Definition
* Wildfires are uncontrolled fires that burn in natural areas like forests or grasslands.
* Climate change contributes to warmer and drier conditions, leading to more dead trees and vegetation.
* These conditions make it easier for wildfires to start and harder to extinguish.
63
Wildfires: Impact on Humans
* Wildfires can cause death, injuries, and burns.
* They release large amounts of carbon dioxide, carbon monoxide, and particulate matter into the atmosphere.
* Air pollution from wildfires leads to respiratory illnesses and deaths.
* Wildfires destroy buildings and property, leading to homelessness and economic losses.
64
Wildfires: Australian Wildfires (2019-2020)
* Widespread wildfires affected the entire continent of Australia.
* Persistent hot and dry conditions, worsened by climate change, made the fires difficult to control.
* Air quality was hazardous, especially in Sydney, where it measured 11 times higher than hazardous levels.
* 34 people died, and thousands of buildings were destroyed, leaving many homeless.
65
Floods: Impact of Climate Change
* Warmer temperatures increase precipitation in some regions.
* Increased snowmelt and rising sea levels contribute to higher flood risks.
* Areas already experiencing high precipitation are especially vulnerable.
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Floods: Impact on Humans
* Floods can cause loss of human lives due to drowning.
* Fast-moving floodwaters can destroy buildings and properties, leading to homelessness and economic losses.
* Floods can contaminate food and water supplies.
* Waterborne diseases, such as cholera, become more prevalent when floodwaters enter drinking water sources.
67
Floods: Bangladesh
* Bangladesh is densely populated and low-lying, with many people living near coastal areas.
* The country has a monsoon climate and frequently experiences seasonal flooding.
* Bangladesh receives meltwater from the Himalayan icecaps and glaciers.
* It is vulnerable to coastal flooding due to sea level rise.
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Tropical Cyclones: Definition
* Tropical cyclones are intense circular storms that form over warm tropical oceans.
* They are characterized by strong winds, heavy rainfall, and storm surges.
* Climate change leads to warmer oceans and more water vapor in the atmosphere, contributing to more intense and frequent tropical cyclones.
69
Tropical Cyclones: Impact on Humans
* Strong winds, heavy rain, and storm surges can result in loss of lives due to flooding, landslides, and collapsed buildings.
* Strong winds can destroy homes and crops, leading to food insecurity and economic losses.
* Power supplies may be cut by strong winds, exacerbating the impact on affected communities.
70
Tropical Cyclones: 2020 Cyclones in the Philippines
* Between October and November 2020, the Philippines was hit by six tropical cyclones.
* Typhoon Goni, the strongest of these storms, caused significant damage with destructive winds and heavy rainfall.
* There was a loss of lives and massive destruction of properties.
* Nearly one million people were evacuated.
* The estimated damage to crops was nearly $36 million.
