subtopic 2.4: climate and biomes
Biomes are groups of ecosystem that have the same climate and dominant communities. They are complex terrestrial (mostly earth's surface) systems of abiotic and biotic factors that cover a large area and are characterized by certain soil & climate characteristics and by certain groupings of plants and animals. Living organisms prefer certain climatic conditions. This means that animal and plants are usually found only in regions that suit them. A polar bear, for example, will be found in a region of low temperature and low humidity. Such a region of the biosphere is called the arctic.
In this unit we will look at the different types of biomes and the factors that influences the organisms in those biomes.
This unit is a minimum of 3 hours
Guiding Questions
In this unit we will look at the different types of biomes and the factors that influences the organisms in those biomes.
This unit is a minimum of 3 hours
Guiding Questions
- How does climate determine the distribution of natural systems?
- How are changes in Earth systems affecting the distribution of biomes?
- What role do human activities play in altering the distribution and characteristics of biomes?
- How do ocean currents and atmospheric circulation patterns influence regional climates and biomes?
Understanding:
2.4.1 Climate describes atmospheric conditions over relatively long periods of time, whereas weather describes the conditions in the atmosphere over a short period of time.
- Distinguish between weather and climate
https://www.youtube.com/watch?v=cBdxDFpDp_k&pp=ygUSd2VhdGVyaCB2cyBjbGltYXRl
Understanding the difference between climate and weather is important for grasping how atmospheric conditions vary over different time periods.
Weather
Weather
- Weather describes the specific atmospheric conditions at a particular time or over a short period.
- It includes variables such as temperature, humidity, air pressure, wind speed, and precipitation.
- Weather can change within minutes, hours, or days.
- Weather conditions are specific to a particular place and can vary greatly over short distances.
- Examples:
- A rainy day in your city.
- A thunderstorm occurring in the afternoon.
- Climate is the average of weather conditions over a long period, typically 30 years.
- It represents long-term patterns of temperature, precipitation, and other weather variables.
- Climate is observed over decades.
- Climate can describe conditions in a specific region or around the world
- Examples:
- The hot, dry summers and mild, wet winters of the Mediterranean climate.
- The cold, snowy winters and warm, humid summers of a continental climate.
2.4.2 A biome is a group of comparable ecosystems that have developed in similar climatic conditions, wherever they occur.
- Explain how precipitation influences the distribution of plant species in a biome.
- Describe the impact of temperature on the types of vegetation found in boreal forests and deserts.
- Outline the role insolation plays in the productivity of ecosystems within tropical rainforests
A biome is a large geographical area that contains distinct plant and animal groups, adapted to the region's specific climate and environment. Each biome is made up of multiple ecosystems that share similar climatic conditions, such as temperature, precipitation, and insolation (sunlight exposure). These shared conditions lead to the development of parallel features among ecosystems within the same biome, even if they are located in different parts of the world.
Key Characteristics of Biomes
Key Characteristics of Biomes
- Precipitation: The amount and distribution of rainfall or snowfall in a region. This is a critical factor in determining the types of vegetation and animal life that can thrive in a biome. For example, deserts receive very little rainfall, resulting in sparse vegetation, while tropical rainforests receive abundant rainfall, supporting lush, diverse plant and animal life.
- Temperature: The range of temperatures that a region experiences throughout the year. Temperature influences the types of organisms that can survive in a biome. For instance, tundra biomes are characterized by very low temperatures and short growing seasons, supporting cold-adapted plants and animals. In contrast, tropical rainforests have consistently warm temperatures year-round.
Credit: David Bice © Penn State University is licensed under CC BY-NC-SA 4.0
- Insolation: The amount of solar radiation that reaches a given area. Insolation affects the energy available for photosynthesis, which in turn impacts the productivity of ecosystems. High insolation in equatorial regions supports dense, biodiverse forests, while lower insolation in polar regions limits the growth of vegetation.
https://www.solar-facts-and-advice.com/insolation.html
2.4.3 Abiotic factors are the determinants of terrestrial biome distribution.
- Describe how temperature and rainfall influence the distribution of two specific biomes.
- Explain how latitude affects the distribution of biomes on Earth.
Abiotic factors, such as temperature, rainfall, latitude, and elevation, play crucial roles in determining the distribution of terrestrial biomes. Each biome is characterized by specific climate conditions, which influence the types of ecosystems that develop in different regions. Understanding these factors helps us comprehend the diversity of life on Earth and how ecosystems are shaped by their physical environment.
Key Abiotic Factors Determining Biome Distribution
Key Abiotic Factors Determining Biome Distribution
- Temperature:
- Temperature affects the metabolic rates of organisms, the length of growing seasons, and the types of vegetation that can survive in an area.
- Biomes can be classified along a temperature gradient, from cold polar regions to warm tropical areas.
- Rainfall:
- Rainfall influences soil moisture, water availability, and the types of vegetation that can thrive.
- Biomes can also be classified along a rainfall gradient, from arid deserts to wet rainforests.
- Latitude:
- Latitude affects the amount of solar energy received, which influences temperature and daylight hours.
- Latitude Zones:
- Tropical Zones: Located near the equator, characterized by warm temperatures and high rainfall.
- Temperate Zones: Located between the tropics and polar regions, characterized by moderate temperatures and seasonal changes.
- Polar Zones: Located near the poles, characterized by very cold temperatures and low precipitation.
- Elevation:
- Elevation affects temperature, with higher elevations being colder. It also influences oxygen levels and atmospheric pressure.
- Biomes can change with altitude, similar to changes with latitude.
- Low Elevations: Generally warmer and support diverse plant and animal life.
- High Elevations: Colder with specialized flora and fauna adapted to harsher conditions.
https://socratic.org/questions/how-are-biomes-distributed-1
Climate Graphs
Climate graphs are commonly employed to visualize the average temperature and rainfall patterns observed at a specific location throughout the year. These graphs typically comprise a continuous red line representing the average monthly temperature and a straightforward bar graph depicting the average monthly rainfall amounts.
Climate graphs are commonly employed to visualize the average temperature and rainfall patterns observed at a specific location throughout the year. These graphs typically comprise a continuous red line representing the average monthly temperature and a straightforward bar graph depicting the average monthly rainfall amounts.
https://worldbiomestask.weebly.com/climate.html
Application of skills: Create climate graphs showing annual precipitation/average temperature for different biomes.
2.4.4 Biomes can be categorized into groups that include freshwater, marine, forest, grassland,
desert and tundra. Each of these groups has characteristic abiotic limiting factors, productivity and
diversity. They may be further classed into many subcategories (for example, temperate forests,
tropical rainforests and boreal forests).
desert and tundra. Each of these groups has characteristic abiotic limiting factors, productivity and
diversity. They may be further classed into many subcategories (for example, temperate forests,
tropical rainforests and boreal forests).
- Define biome
- List the five major classes of biomes.
- Explain the distributions, structure, biodiversity, and relative productivity of four pairs of contrasting biomes.
- Use case studies to explain the distribution, structure, limiting factors, productivity and biodiversity of contrasting biomes.
There are two basic categories of communities: terrestrial (land) and aquatic (water). These two basic types of community contain smaller units known as biomes. A biome is a large-scale category containing many communities of a similar nature, whose distribution is largely controlled by climate
https://www.geographyalltheway.com/igcse_geography/gcse-ecosystems/biomes_ecosystems.htm
A biome has distinctive abiotic factors and species which distinguish it from other biomes. Water, insolation and temperature are the climate controls important when understanding how biomes are structured, how they function and where they are found round the world. Biomes usually cross national boundaries (biomes do not stop at a border; for example, the Sahara, tundra, tropical rainforests).
- Aquatic - which are further subdivided into:
- Freshwater: ponds and lakes, streams and rivers and wetlands such as bogs and swamps.
- Marine: deep ocean, coral reefs, estuaries and mangrove swamps.
- Terrestrial biomes are land-based biomes
- Forest – tropical rainforest, temperate forests and boreal or taiga.
- Grassland – savanna and temperate.
- Desert – hot, coastal and cold.
- Tundra – arctic and alpine.
Refer to prevailing climate and limiting factors. For example, tropical rainforests are found close to the equator where there is high insolation and rainfall and where light and temperature are not limiting. The other biome may be, for
example, temperate grassland or a local example. Limit climate to temperature, precipitation and insolation. It is required that you need to be able to explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and one other biome. Climate should only be explained in terms of temperature, precipitation and insolation only.
example, temperate grassland or a local example. Limit climate to temperature, precipitation and insolation. It is required that you need to be able to explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and one other biome. Climate should only be explained in terms of temperature, precipitation and insolation only.
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Deserts:
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Tundra:
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Tropical rainforest:
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Temperate forest:
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Grasslands (tropical and temperate)
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Aquatics (freshwater, coral reefs deep oceans)
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You should study at least four contrasting pairs of biomes. Examples of contrasting biomes include; temperate forests and tropical seasonal forests; tundra and deserts; tropical coral reefs and hydrothermal vents; temperate bogs and tropical mangrove forests.
Climate plays an important role in the development of biomes. Robert Whittaker, an American ecologist, plotted rainfall vs. temperature for points all over the globe on a single graph (see below). He then looked at what biomes had developed at those sites, and was able to group the different biomes according to mean annual temperature and precipitation, as the shaded areas in the graph below indicate.
Note that in Whittaker's diagram the temperature axis is reversed; that is temperature goes DOWN as you move to the right. Theoretically, if you know the average temperature and precipitation for a site, you should be able to predict what biome will develop there.
Note that in Whittaker's diagram the temperature axis is reversed; that is temperature goes DOWN as you move to the right. Theoretically, if you know the average temperature and precipitation for a site, you should be able to predict what biome will develop there.
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2.4.5 The tricellular model of atmospheric circulation explains the behaviour of atmospheric systems and the distribution of precipitation and temperature at different latitudes. It also explains how these factors influence the structure and relative productivity of different terrestrial biomes.
- Describe how the tricellular model contributes to the distribution of biomes
The tricellular model explains the distribution of precipitation and temperature and how they influence structure and relative productivity of different terrestrial biomes. The tricellular model is made up of three different air masses, these control atmospheric movements and the redistribution of heat energy. The three air masses, starting from the equator, are called the Hadley cell, Ferrel cell and the polar cell.
The tricellular model also contains the ITCZ (Inter-tropical convergence zone), this is the meeting place of the trade winds from both the northern hemisphere and the southern hemisphere. The ITCZ is a low pressure area where the trade winds, which have picked up latent heat as they crossed oceans, are now forced to rise by convection currents. These rising convection currents are then cooled adiabatically to form massive cumulonimbus clouds.
The tricellular model also contains the ITCZ (Inter-tropical convergence zone), this is the meeting place of the trade winds from both the northern hemisphere and the southern hemisphere. The ITCZ is a low pressure area where the trade winds, which have picked up latent heat as they crossed oceans, are now forced to rise by convection currents. These rising convection currents are then cooled adiabatically to form massive cumulonimbus clouds.
- As substance gain heat energy, density decreases so particles rise
- As you go up in altitude air cools, becomes more dense and falls back towards earth’s surface.
- These convection currents drive the Earth’s wind patterns and affect the biomes.
- The same phenomena drives ocean currents
image from ask.revision.co.zw
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Application: Use the tricellular model of atmospheric circulation and link it to the planetary distribution of heat and biomes.
2.4.6 The oceans absorb solar radiation and ocean currents distribute the resulting heat around the world.
- Describe the role of surface and deep ocean currents in distributing heat around the world.
- Explain the process of thermohaline circulation and its significance in global heat distribution.
Oceans play a crucial role in regulating Earth's climate by absorbing solar radiation and distributing heat around the globe through ocean currents. This process helps maintain temperature balance, influences weather patterns, and supports marine and terrestrial ecosystems.
Absorption of Solar Radiation
Absorption of Solar Radiation
- Solar radiation is the energy emitted by the sun that reaches the Earth, including visible light, ultraviolet light, and infrared radiation.
- The oceans absorb about 90% of the solar radiation that reaches the Earth's surface, converting it into heat energy.
- Water has a high heat capacity, meaning it can absorb and store large amounts of heat without a significant increase in temperature.
- Oceans cover about 71% of the Earth's surface, providing a vast area for absorbing solar energy.
- The ability of water to transmit light allows heat to be distributed throughout the upper layers of the ocean.
- Ocean currents are continuous, directed movements of seawater generated by various forces, including wind, temperature differences, salinity variations, and the Earth's rotation.
- Types of Currents:
- Surface Currents: These are driven primarily by wind and affect the upper 400 meters of the ocean.
- Deep Currents: These are driven by differences in water density, which are influenced by temperature (thermohaline circulation) and salinity.
- Heat Distribution:
- Global Conveyor Belt: A large-scale ocean circulation system, often referred to as the thermohaline circulation or global conveyor belt, moves warm water from the equator towards the poles and cold water from the poles towards the equator.
- Moderating Climate: This circulation helps moderate the Earth's climate by distributing heat, which influences weather patterns and climate zones.
- Key Currents:
- Gulf Stream: A powerful, warm Atlantic Ocean current that originates in the Gulf of Mexico and flows along the eastern coast of the United States and across the Atlantic to Europe, significantly warming the climate of nearby regions.
- California Current: A cold Pacific Ocean current that flows southward along the western coast of North America, bringing cooler temperatures to the coastal regions.
2.4.7 Global warming is leading to changing climates and shifts in biomes.
- Discuss how climate change is impacting biomes and causing them to shift.
image from news.mongabay.com
A changing global climate threatens species and ecosystems. The distribution of species is largely determined by climate, as is the distribution of ecosystems and plant vegetation zones (biomes). Climate change may simply shift these distributions, but often, barriers and human presence will provide no opportunity for distributional shifts. For these reasons, some species and ecosystems are likely to be eliminated by climate change.
If significant climate change occur many natural populations of wild organisms will be unable to exist within their natural ranges. Changes in temperature and precipitation, and resultant changes in vegetation and habitat, are likely to seriously affect the suitability of the locales where species are presently found. Thus, climate change is an additional factor threatening the survival of species
Climate changes are happening very fast, within decades, and organisms change slowly, over many generations through evolutionary adaptation. All they can do to adapt to fast change is to move. They move:
In Africa in the Sahel region, woodlands are becoming savannas
If significant climate change occur many natural populations of wild organisms will be unable to exist within their natural ranges. Changes in temperature and precipitation, and resultant changes in vegetation and habitat, are likely to seriously affect the suitability of the locales where species are presently found. Thus, climate change is an additional factor threatening the survival of species
Climate changes are happening very fast, within decades, and organisms change slowly, over many generations through evolutionary adaptation. All they can do to adapt to fast change is to move. They move:
- towards the poles where it is cooler
- higher up mountains where it is cooler
- towards the equator where it is wetter
In Africa in the Sahel region, woodlands are becoming savannas
This climate model projection shows the movement of a midwestern prairie climate into the boreal forest zone
https://newscenter.lbl.gov/2013/05/05/boreal/
Research in ecosystem ecology often examines how climate change affects terrestrial primary production and how ecosystems can absorb CO2 emissions. Terrestrial primary production is vital for sequestering carbon in biomass, reducing atmospheric CO2, a major greenhouse gas. However, studies indicate a decline in terrestrial net primary production (NPP) due to global warming and drought. Similar data from various sources estimate a significant reduction in global terrestrial NPP in recent years. This decline can reduce carbon sequestration, threaten food security, and disrupt food webs.
HL only
This unit is a minimum of 5-6 hours
2.4.8 There are three general patterns of climate types that are connected to biome types.
- Define the three general patterns of climate types and provide one key characteristic of each.
Climate zones refer to regions with unique climate characteristics. These zones are often aligned with specific weather patterns, latitudes, or ecosystems of plants and animals.
Various climate classification systems exist, each defining zones based on different climatic elements or combinations of these elements.
Climate zones are useful for monitoring how environmental conditions vary in particular regions. They aid in understanding the distribution of plant and animal species, including identifying those at risk due to habitat destruction. Additionally, climate zones provide valuable information for farmers and gardeners about which plants are best suited to grow in their specific areas.
The Köppen climate classification is one of the most widely used systems of climate zones. Originally developed by the climatologist Wladimir Köppen in 1884, it has had several revisions and changes over the years but has remained in use by scientists all over the world.
The Köppen system divides climates into five groups based on rainfall and temperature:
There are three general patterns of climate types connected to biome types. These climate types are tropical, temperate, and polar, each characterized by specific temperature and precipitation patterns that support distinct biomes
Various climate classification systems exist, each defining zones based on different climatic elements or combinations of these elements.
Climate zones are useful for monitoring how environmental conditions vary in particular regions. They aid in understanding the distribution of plant and animal species, including identifying those at risk due to habitat destruction. Additionally, climate zones provide valuable information for farmers and gardeners about which plants are best suited to grow in their specific areas.
The Köppen climate classification is one of the most widely used systems of climate zones. Originally developed by the climatologist Wladimir Köppen in 1884, it has had several revisions and changes over the years but has remained in use by scientists all over the world.
The Köppen system divides climates into five groups based on rainfall and temperature:
- Tropical climates (A)
- Dry climates (B)
- Temperate climates (C)
- Continental climates (D)
- Polar climates (E)
There are three general patterns of climate types connected to biome types. These climate types are tropical, temperate, and polar, each characterized by specific temperature and precipitation patterns that support distinct biomes
.Tropical Climates
- Location: Near the equator.
- Temperature and Humidity: High temperatures and humidity.
- Types:
- Equatorial Tropical Climates:
- Temperature: Consistently high year-round.
- Rainfall: High year-round.
- Biomes: Lush, biodiverse rainforests.
- Wet Season: Marked by heavy rains and warm temperatures, supporting abundant vegetation.
- Dry Season: Characterized by drought conditions.
- Biomes: Tropical rainforests, tropical grasslands (savannas), and hot deserts.
- Location: Mid-latitude regions.
- Temperature: Moderate with distinct seasons.
- Types:
- Maritime Temperate Climates:
- Location: Typically near coastlines.
- Temperature: Milder winters and cooler summers.
- Humidity and Precipitation: Higher humidity and more consistent rainfall due to the ocean's moderating influence.
- Biomes: Temperate forests and temperate rainforests.
- Location: Found inland, away from large water bodies.
- Temperature: More extreme variations with colder winters and hotter summers.
- Humidity and Precipitation: Less humidity, greater seasonal variation in precipitation, and overall drier conditions.
- Biomes: Temperate forests and temperate grasslands.
- Location: Near the Earth's poles.
- Temperature: Extremely cold year-round.
- Seasons:
- Winters: Long, harsh with very low temperatures.
- Summers: Short, cool.
- Precipitation: Minimal, mostly snow.
- Biomes: Arctic tundra and boreal forests (taiga).
2.4.9 The biome predicted by any given temperature and rainfall pattern may not develop in an area because of secondary influences or human interventions.
- Explain how urbanization can prevent the natural development of a biome that would be predicted by temperature and rainfall patterns
- Describe the impact of agriculture on the natural development of biomes and give one specific example
- Discuss the role of deforestation in altering the characteristics and distribution of biomes.
While temperature and rainfall are primary determinants of biome distribution, secondary influences and human interventions can significantly alter the natural development of biomes. Understanding these factors is crucial, especially in areas with high human population densities such as temperate and tropical climates, where urbanization, agriculture, and deforestation are prevalent.
Urbanization:
Deforestation:
Urbanization:
- Impact:
- Urbanization replaces natural habitats with buildings, roads, and other infrastructure to meet human needs.
- Consequences:
- Disruption of biogeochemical cycles.
- Fragmentation and loss of habitats, threatening species and leading to potential ecosystem collapse.
- Alteration of local climates, creating urban heat islands.
- Interruption of natural water flows and increased pollution.
Deforestation:
- Impact:
- Removing large numbers of trees from forests leads to habitat loss, affecting biodiversity and ecosystem functions.
- Consequences:
- Disruption of biogeochemical flows, especially carbon and water cycles.
- Degradation of soil health, increasing erosion and reducing fertility.
- Alteration of local climates, potentially changing precipitation patterns and temperatures.
- Contribution to global climate change through increased carbon emissions.
Agriculture:
- Impact:
- Agriculture transforms biomes by replacing diverse natural habitats with monocultures and less diverse crops.
- Consequences:
- Disruption of biogeochemical flows, particularly nitrogen and phosphorus cycles.
- Simplification of food webs, reducing biodiversity.
- Alteration of soil composition and water availability, impacting local climates.
- Potential shifts in the distribution and characteristics of nearby biomes due to changed environmental conditions.
2.4.10 The El Niño Southern Oscillation (ENSO) cycle is the fluctuation in wind and sea surface temperatures that characterizes conditions in the tropical Pacific Ocean. The two opposite and extreme states are El Niño and La Niña, with transitional and neutral states between the extremes.
- Define the El Niño Southern Oscillation (ENSO) cycle and describe its two extreme states.
- Explain how El Niño conditions affect weather patterns in the eastern and western Pacific regions.
- Discuss the challenges in predicting the frequency and intensity of El Niño and La Niña events.
The El Niño Southern Oscillation (ENSO) cycle is a significant climate phenomenon characterized by fluctuations in wind patterns and sea surface temperatures in the tropical Pacific Ocean. This cycle includes two extreme states—El Niño and La Niña—along with transitional and neutral states between these extremes. The frequency and intensity of ENSO events are irregular and challenging to predict, making them a critical area of study for understanding global climate variability.
https://www.weather.gov/mhx/ensowhat
The ENSO Cycle
Irregularity and Predictability
- El Niño:
- Characteristics:
- Warmer than average sea surface temperatures in the central and eastern Pacific Ocean.
- Weakened trade winds or even a reversal of their usual direction.
- Impacts:
- Can lead to increased rainfall and flooding in the eastern Pacific regions, such as the western coast of South America, and drought conditions in the western Pacific, including Australia and Indonesia.
- Alters weather patterns globally, influencing temperature and precipitation in various regions, such as warmer winters in North America and increased rainfall in the southern United States.
- Characteristics:
- La Niña:
- Characteristics:
- Cooler than average sea surface temperatures in the central and eastern Pacific Ocean.
- Strengthened trade winds.
- Impacts:
- Typically opposite to those of El Niño, leading to dry conditions in the eastern Pacific and wetter conditions in the western Pacific.
- Can cause colder winters in the northern United States, increased hurricane activity in the Atlantic, and heavy rains in Australia and Indonesia.
- Characteristics:
- Neutral State:
- Neither El Niño nor La Niña conditions prevail, with sea surface temperatures and wind patterns close to the long-term average.
- More stable and predictable weather patterns compared to the extreme states.
- Transitional States:
- Periods of transition between El Niño and La Niña conditions, marked by gradual changes in sea surface temperatures and wind patterns.
- Weather patterns can be variable and unpredictable during these transitional phases.
Irregularity and Predictability
- Frequency and Intensity:
- The occurrence of El Niño and La Niña events is not regular, and their intensity can vary significantly from one event to another.
- Some periods may experience frequent and intense events, while others may have long intervals with fewer and weaker events.
- Challenges in Prediction:
- ENSO involves complex interactions between the ocean and the atmosphere, making it difficult to predict with high accuracy.
- Climate models and forecasting tools have improved but still face challenges in predicting the exact timing, duration, and intensity of ENSO events.
- Weather Extremes:
- El Niño: Increased likelihood of extreme weather events such as heavy rains, floods, and heatwaves.
- La Niña: Increased risk of droughts, cold spells, and intensified hurricane seasons.
2.4.11 El Niño is due to a weakening or reversal of the normal east–west (Walker) circulation, which increases surface stratification and decreases upwelling of cold, nutrient-rich water near the coast of north-western South America. La Niña is due to a strengthening of the Walker circulation and reversal of other effects of El Niño.
- Define El Niño and La Niña and explain how the Walker Circulation changes during these events.
- Describe how El Niño affects upwelling and marine productivity off the coast of north-western South America.
- Discuss the role of sea surface temperatures in the development of El Niño and La Niña events
El Niño and La Niña are extreme phases of the El Niño Southern Oscillation (ENSO) cycle, characterized by changes in the normal east-west (Walker) circulation of the tropical Pacific Ocean. These events significantly impact global weather patterns and marine ecosystem productivity, particularly in the tropics and subtropics.
Development of El Niño and La Niña Events
Development of El Niño and La Niña Events
- El Niño:
- During El Niño, the normal east-west trade winds weaken or reverse. The Walker Circulation, which typically moves warm water from the eastern Pacific to the western Pacific, is disrupted.
- The weakened winds allow warm water to accumulate in the central and eastern Pacific Ocean, increasing surface temperatures.
- Increased surface stratification decreases the upwelling of cold, nutrient-rich water near the coast of north-western South America, leading to reduced marine productivity.
- La Niña:
- In contrast, La Niña is characterized by a strengthening of the Walker Circulation. The trade winds become stronger, enhancing the movement of warm water towards the western Pacific.
- This strengthens upwelling in the eastern Pacific, bringing colder, nutrient-rich water to the surface.
- The increased upwelling boosts marine productivity near the coast of north-western South America.
Impacts on Global Weather Patterns
- El Niño Weather Patterns:
- South America: Increased rainfall and flooding in western coastal regions, such as Peru and Ecuador.
- North America: Warmer winters and increased rainfall in the southern United States; drier conditions in the Pacific Northwest.
- Australia and Indonesia: Drier conditions leading to droughts and increased risk of wildfires.
- Productivity Impact: Reduced upwelling off the coast of South America leads to lower marine productivity, affecting fisheries and marine biodiversity.
- La Niña Weather Patterns:
- South America: Drier conditions in the western coastal regions, leading to reduced flooding and more stable weather.
- North America: Colder winters in the northern United States; increased hurricane activity in the Atlantic.
- Australia and Indonesia: Increased rainfall leading to flooding and enhanced agricultural productivity.
- Productivity Impact: Enhanced upwelling off the coast of South America increases marine productivity, benefiting fisheries and marine ecosystems.
https://earth.org/data_visualization/what-are-el-nino-and-la-nina/
Examples of Resulting Weather Patterns and Ecosystem Changes
- El Niño Example: Peru
- Increased rainfall leading to severe flooding, landslides, and destruction of infrastructure.
- Reduced upwelling decreases fish populations, impacting local fishing industries and marine biodiversity.
- La Niña Example: Australia
- Increased rainfall leading to widespread flooding, benefiting agricultural productivity but also causing flood damage.
- Enhanced marine productivity in the eastern Pacific boosts fish populations, supporting fisheries and biodiversity.
2.4.12 Tropical cyclones are rapidly circulating storm systems with a low-pressure centre that originate in the tropics and are characterized by strong winds.
- Describe tropical cyclone main characteristics.
- Explain how the classification of a tropical cyclone as a hurricane or typhoon is determined
- Discuss the impacts of tropical cyclones on coastal communities, focusing on wind damage, flooding, and storm surges.
https://www.sciencemediacentre.co.nz/2020/02/15/tropical-cyclones-expert-qa/
Tropical cyclones are powerful and rapidly circulating storm systems that originate in the tropics. They are characterized by a low-pressure center, strong winds, and heavy rainfall. Depending on their location, tropical cyclones are classified as hurricanes or typhoons once their sustained wind speeds exceed 119 km/hr.
Characteristics of Tropical Cyclones
Characteristics of Tropical Cyclones
- Formation:
- Tropical cyclones form over warm ocean waters in the tropics.
- hey develop when sea surface temperatures are above 26.5°C (80°F), which provides the necessary heat and moisture to fuel the storm.
- The storm system features a low-pressure center, also known as the eye, surrounded by strong winds and thunderstorms.
- Structure:
- Eye: The calm, clear center of the storm with the lowest pressure.
- Eye Wall: The area surrounding the eye with the most intense winds and heavy rainfall.
- Rainbands: Bands of thunderstorms that spiral outward from the eye wall, bringing heavy rain and strong winds.
- Movement:
- Tropical cyclones rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere due to the Coriolis effect.
- Their path is influenced by global wind patterns and the Earth's rotation.
Classification of Tropical Cyclones
- Hurricanes:
- Tropical cyclones that form in the Atlantic Ocean or the northeastern Pacific Ocean are called hurricanes.
- Classified as a hurricane once sustained wind speeds exceed 119 km/hr (74 mph).
- Typhoons:
- Tropical cyclones that form in the northwestern Pacific Ocean are called typhoons.
- Classified as a typhoon once sustained wind speeds exceed 119 km/hr (74 mph).
- Cyclones:
- In the Indian Ocean and South Pacific, tropical cyclones are simply referred to as cyclones.
- Classified similarly to hurricanes and typhoons once sustained wind speeds exceed 119 km/hr (74 mph).
Impacts of Tropical Cyclones
- Strong Winds:
- High wind speeds can cause extensive damage to buildings, infrastructure, and vegetation.
- Winds can turn debris into dangerous projectiles, posing significant risks to life and property.
- Heavy Rainfall:
- Intense rainfall can lead to severe flooding, damaging homes, crops, and infrastructure.
- Saturated soils can trigger landslides in hilly or mountainous regions, causing further destruction.
- Storm Surge:
- The strong winds and low pressure of tropical cyclones can push large volumes of seawater onto coastal areas, causing storm surges that lead to severe coastal flooding and erosion.
Predicting and Preparing for Tropical Cyclones
- Monitoring Systems:
- Satellites: Provide real-time images and data on storm development and movement.
- Weather Stations: Collect data on wind speeds, pressure, and precipitation to track and predict storm paths.
- Preparedness Measures:
- Evacuation Plans: Communities in vulnerable areas should have evacuation plans in place to move people to safety before the storm hits.
- Building Codes: Enforcing building codes that require structures to withstand high winds and flooding can reduce damage and save lives.
- Public Awareness: Educating the public about the risks and safety measures can help minimize the impacts of tropical cyclones.
2.4.13 Rises in ocean temperatures resulting from global warming are increasing the intensity and frequency of hurricanes and typhoons because warmer water and air have more energy.
- Define the relationship between global warming and the intensity of hurricanes and typhoons.
- Explain how rising sea surface temperatures contribute to the formation and intensification of tropical cyclones.
- Describe the impact of warmer ocean waters on the frequency and duration of hurricanes and typhoons.
Global warming, driven by the increase in greenhouse gases, is causing a rise in ocean temperatures. Warmer ocean waters and air have more energy, which contributes to the increased intensity and frequency of hurricanes and typhoons. This understanding is crucial as it highlights the connection between climate change and extreme weather events.
The Relationship Between Ocean Temperatures and Storm Intensity
The Relationship Between Ocean Temperatures and Storm Intensity
- Energy Source:
- Hurricanes and typhoons draw energy from warm ocean waters. Higher temperatures provide more energy, fueling the storms and making them more intense.
- Warm air holds more moisture, which contributes to heavier rainfall and stronger winds during storms.
- Storm Development:
- As ocean temperatures rise, storms can develop more rapidly and reach higher wind speeds.
- Warmer waters can sustain storms for longer periods, allowing them to travel further and cause more damage.
The graph illustrates Accumulated Cyclone Energy (ACE), an index that quantifies the activity of a cyclone or hurricane season. ACE takes into account the number of hurricanes, their duration, and their intensity.
The impacts of more powerful storms are extensive and profound:
The impacts of more powerful storms are extensive and profound:
- Elevated storm surges that flood coastal regions and force community evacuations.
- Enhanced inland flooding, resulting in property damage and disruption to infrastructure.
- Intensified winds that cause widespread power outages and significant structural damage.
- Increased rainfall, leading to landslides and complicating existing water management issues.
Evidence of Increases in Hurricanes and Typhoons
Scientific Studies:
Impact of Increased Hurricane and Typhoon Activity
- Historical Data:
- Studies show an increase in the frequency of hurricanes and typhoons over the past few decades. For example, the North Atlantic has seen a significant rise in the number of named storms since the 1970s.
- There is a clear trend of increasing storm intensity. The proportion of Category 4 and 5 hurricanes has increased, indicating more powerful storms.
- Recent Examples:
- Hurricane Katrina (2005): One of the most intense and damaging hurricanes in U.S. history, fueled by exceptionally warm Gulf of Mexico waters.
- Typhoon Haiyan (2013): One of the strongest typhoons ever recorded, with sustained winds reaching 315 km/h (195 mph), impacting the Philippines severely.
- Hurricane Maria (2017): A Category 5 hurricane that caused catastrophic damage in Puerto Rico, exacerbated by high sea surface temperatures.
Scientific Studies:
- Climate Models: Models predict an increase in the frequency and intensity of tropical cyclones as global temperatures continue to rise. These models are based on observed data and simulations of future climate scenarios.
- IPCC Reports: The Intergovernmental Panel on Climate Change (IPCC) reports highlight the connection between global warming and the increasing strength of tropical cyclones, supported by extensive research and data analysis.
- Temperature Records:
- Sea Surface Temperatures: NOAA and other organizations have recorded consistent increases in sea surface temperatures over the past century, correlating with the observed increase in storm activity.
- Heat Content: The overall heat content of the upper ocean layers has risen, providing more fuel for storm formation and intensification.
Impact of Increased Hurricane and Typhoon Activity
- Coastal Damage:
- Stronger storms cause more extensive damage to buildings, roads, and other infrastructure.
- Increased storm activity accelerates coastal erosion, affecting habitats and human settlements.
- Human Impact:
- More intense storms lead to higher casualties and force more people to evacuate and relocate.
- The financial burden of storm damage is growing, with billions of dollars spent on recovery and rebuilding efforts.
- Environmental Consequences:
- Strong storms can devastate ecosystems, such as coral reefs and mangroves, which are critical for coastal protection and biodiversity.
- Flooding and storm surges can lead to contamination of water supplies and spread pollutants, impacting both human health and the environment.
Key Terms
|
weather:
climate: biome: insolation: precipitation: temperature: Coriolis Effect: ccean currents: Intertropical Convergence Zone (ITCZ): HL ONLY Great Ocean Conveyor Belt: El Niño: La Niña: accumulated cyclone energy (ACE): tropical cyclone: hurricanes, typhoons, thermohaline ENSO cycle walker circulation upwelling stratification |
latitude:
altitude: rain shadow climatograph tricellular model: Hadley Cell: Ferrel Cell: Polar Cell:. Biome Shift |
desert
temperate grassland arid permafrost tropical rainforest taiga (boreal) savanna temperate forest |
biomes
arctic tundra productivity understory scrub-lands grazing precipitation gross productivity latitude |
savanna
temperate forest canopy evergreen broad leaf browsing latitude temperature |
Classroom Materials
| Subtopic 2.4 Climate and Biomes Presentation.pptx |
| Subtopic 2.4 Climate and Biomes Workbook.docx |
Virtual Biomes Activity - Ask A Biologists
Ecosystems, Organisms and Trophic Levels Simulation - McGraw Hill
The Biome Map questions and Instructions
Biome Comparison Project
Biome Matrix
Climatograph Biomes_worksheet
Construction Climate graphs worksheet
The Disappearing Rain-forest article
Case Studies
- Explain the distributions, structure, biodiversity and relative productivity of two pairs of contrasting biomes (eg. tropical vs. temperate forest, desert vs. tundra)
Correct use of terminology is a key skill in ESS. It is essential to use key terms correctly when communicating your understanding, particularly in assessments. .
Useful Links
Blue Planet
The World's Biomes - Berkeley University
Land Biomes - About Biology
Aquatic Biomes - About Biology
Biomes Animation - McGraw-Hill
Terrestrial biomes - Berkeley University
Biomes and Ecosystems - Window 2 The Universe
Interactive Biomes - Marietta College
Biome Game - Earth Observatory
Global Ecology - The Global Education Project
Introduction to Biomes - Earth Labs
Rebuilding a Rainforest from Scratch - Scientific America
Biomes and Climate Graphs
This activity, prepared by TES, will help you better understand the relationship between temperatures, precipitation and specific biomes.
In The News
Rainforest Reduction - BBC Travel 02 November 2012
Amazon Rainforest: The Earth's Lungs - BBC Future 27 February 2013
Ecological Services of Mangrove Forests - BBC Future 13 February 2013
Nutrients from Deserts - BBC Future 6 February 2013
Blue Planet
The World's Biomes - Berkeley University
Land Biomes - About Biology
Aquatic Biomes - About Biology
Biomes Animation - McGraw-Hill
Terrestrial biomes - Berkeley University
Biomes and Ecosystems - Window 2 The Universe
Interactive Biomes - Marietta College
Biome Game - Earth Observatory
Global Ecology - The Global Education Project
Introduction to Biomes - Earth Labs
Rebuilding a Rainforest from Scratch - Scientific America
Biomes and Climate Graphs
This activity, prepared by TES, will help you better understand the relationship between temperatures, precipitation and specific biomes.
In The News
Rainforest Reduction - BBC Travel 02 November 2012
Amazon Rainforest: The Earth's Lungs - BBC Future 27 February 2013
Ecological Services of Mangrove Forests - BBC Future 13 February 2013
Nutrients from Deserts - BBC Future 6 February 2013
Theory of knowledge:
- "To what extent does our understanding of natural phenomena, such as climate patterns and extreme weather events, rely on the interpretation of scientific data and models, and how might this affect the ways in which we address global environmental challenges?"
International-mindeness
- "Understanding the global interconnectedness of climate patterns and extreme weather events highlights the importance of international cooperation and collective action in addressing environmental challenges. By recognizing the shared impact of climate change across borders, we can foster a sense of global responsibility and work together to create sustainable solutions for the benefit of all communities worldwide."
Video Clips
Planet Earth Episode 1 From Pole to Pole | BBC Documentary
In this video Paul Andersen describes both weather and climate. Weather is the day-to-day conditions on the Earth's surface, including temperature, wind, humidity, air pressure, and precipitation. Climate are the long term conditions on the Earth's surface. Both climate and weather are determined by sunlight, water, landforms and life forms
The Ocean is essential to life on Earth. Most of Earth's water is stored in the ocean. Although 40 percent of Earth's population lives within, or near coastal regions- the ocean impacts people everywhere. Without the ocean, our planet would be uninhabitable. This animation helps to convey the importance of Earth's oceanic processes as one component of Earth's interrelated systems.
Satellite-based passive microwave images of the sea ice have provided a reliable tool for continuously monitoring changes in the Arctic ice since 1979. Every summer the Arctic ice cap melts down to what scientists call its "minimum" before colder weather begins to cause ice cover to increase. The ice parameters derived from satellite ice concentration data that are most relevant to climate change studies are sea ice extent and sea ice area. This graph displays the area of the minimum sea ice coverage each year from 1979 through 2013. In 2013, the Arctic minimum sea ice covered an area of 4.704 million square kilometers.
Review of some basic properties of the marine intertidal ecosystem
