5.12-5.16 Climate Change

What is climate change? (1)

Climate change is a long-term, significant change in the weather patterns of a region, usually occurring over several decades.

What is a causal relationship? (1)

A causal relationship means that changes in one factor (e.g. temperature) directly cause changes in another factor (e.g. growth rate or hatch rate) because all other variables are controlled.

What is one common cause of modern day climate change? (1)

Although natural changes do occur, the term "climate change" is now commonly used to describe changes caused by humans.

What is global warming? (1)

Global warming is a type of climate change that refers to the rapid increase in global temperature over the last century.

What is an example of how global warming causes other types of climate change? (1)

Global warming can affect rainfall patterns and seasonal cycles, which are types of climate change.

What are three observable effects of global warming on the environment? (3)

- Polar ice and glaciers are retreating.

- Sea levels are rising more quickly.

- pH levels in oceans and rivers are falling due to increased CO₂.

What are two types of evidence for climate change? (2)

- CO2 levels

- Temperature records

How are temperature records used to provide evidence for climate change? (3)

- Since the 1850s, thermometers have been used to measure temperature around the world.

- These provide a reliable but short-term temperature record.

- The general trend of increasing average global temperature since 1910 provides evidence that climate change is happening.

What is dendrochronology? (1)

Dendrochronology is the study of tree rings to determine the age of a tree and the climate conditions during each year of growth.

How often do trees grow new rings? (1)

Trees grow one ring per year.

What determines the thickness of tree rings? (1)

The thickness of each ring depends on the climate during that year.

What do thick tree rings indicate? (1)

Thick rings form in warmer, wetter years when conditions for growth are better.

What do very thin tree rings indicate? (1)

Very thin rings can indicate drought conditions.

What is the difference between light and dark tree rings? (1)

Light-coloured rings indicate fast spring/summer growth, while dark rings indicate slower autumn growth.

How can tree rings provide evidence for climate change? (1)

A trend of increasingly thicker rings from 1920 to 2000 suggests that the climate became warmer over the last century.

What are peat bogs? (1)

Peat bogs are acidic wetland areas.

How is pollen preserved in peat bogs? (1)

Pollen is preserved in layers within peat bogs, with older pollen found deeper down.

How can pollen in peat bogs be used as evidence for climate change? (2)

- Scientists extract the pollen, identify the plant species, and compare it to those that grow in today's climate.

- Because each plant grows in specific climates, changes in the types and amounts of pollen suggest that climate conditions have changed over time.

Why does preserved pollen only come from mature plants? (1)

Only fully grown plants produce pollen, so pollen in a layer shows which plants were successful at that time.

How can an increase in pollen from warm-climate plants be evidence of climate change? (1)

If pollen from plants that grow in warmer climates increases over time, it suggests a rise in temperature.

How can a decrease in pollen from cool-climate plants be evidence of climate change? (1)

If pollen from plants that thrive in cooler climates decreases over time, it shows the climate has become warmer.

Why do the conditions in peat bogs prevent decomposition? (4)

- The conditions in peat bogs are anaerobic.

- This results in less aerobic respiration by decomposers.

- The acidic conditions inhibit or denature enzymes.

- As a result, enzymes cannot digest or break down organic material.

How can ice cores provide evidence for climate change? (3)

- Ice cores are taken from deep layers of ice, where deeper layers are older.

- The ice contains trapped air bubbles with different levels of carbon dioxide.

- By analysing CO₂ levels in bubbles at different depths, scientists can detect how the atmosphere has changed over time.

What are anthropogenic changes? (1)

Anthropogenic causes refer to climate change that is caused by human activities.

How do humans enhance the greenhouse effect? (1)

Humans increase the amount of greenhouse gases, such as CO₂, in the atmosphere by activities like burning fossil fuels.

How do greenhouse gases cause an increase in the Earth's surface temperature? (3)

- Greenhouse gases are released by burning fossil fuels and from livestock.

- These gases trap infrared radiation in the atmosphere.

- This causes Earth's surface temperature to rise, contributing to global warming.

How does deforestation contribute to global warming? (1)

Deforestation removes trees that store carbon, and decomposers release more carbon as they break down dead plant matter.

How do livestock and thawing permafrost contribute to global warming? (1)

Livestock and thawing permafrost release methane, which increases the greenhouse effect and raises global temperatures.

What are three reasons why some people deny human-caused climate change? (3)

- They say CO₂ is released naturally (e.g. volcanoes).

- They claim climate models are inaccurate.

- They believe climate changes naturally and past events don't predict the future.

What are the two greenhouse gases that contribute to global warming? (2)

- Carbon dioxide

- Methane

What are the main sources of carbon dioxide? (3)

- Burning fossil fuels

- Deforestation

- Decomposition of organic matter

What are the main sources of methane? (4)

- Cattle

- Rotting waste

- Melting frozen ground

- Extracting fossil fuels

How has atmospheric carbon dioxide levels changed since the mid-19th century? (3)

- CO₂ concentration has increased by over 100 parts per million since the mid-19th century.

- It had been stable for the past 10,000 years before that.

- This increase is linked to burning fossil fuels (like coal, oil, and gas) and deforestation.

How have methane levels changed due to human activity? (3)

- Methane levels have more than doubled since the mid-19th century.

- This is due to more fossil fuel extraction, more waste, and more livestock farming.

- Methane is also released from thawing permafrost, which stores methane underground.

How should you interpret evidence for causes of climate change? (2)

- You should interpret data on CO₂ levels and temperature to identify correlations.

- A correlation shows a relationship, but it does not prove that one variable causes the other.

How can climate change data be used to make predictions? (2)

- Scientists can extrapolate existing data on atmospheric greenhouse gas concentrations to predict how the climate may change in the future.

- These predictions are called emissions scenarios and are used to model possible outcomes for global climate, including temperature changes.

What scientific body produces climate change predictions? (2)

- The Intergovernmental Panel on Climate Change (IPCC) is a group of international scientists who develop emissions scenarios.

- These are predictions about how human greenhouse gas emissions could change up until 2100.

What is Scenario 1 in the IPCC emissions predictions? (1)

Minimum emissions - greenhouse gas emissions peak and then reduce, as humans take major action.

What are Scenarios 2 and 3 in the IPCC emissions predictions? (1)

Stabilising scenarios - emissions continue to rise but eventually level off.

What is Scenario 4 in the IPCC emissions predictions? (1)

Maximum emissions - emissions keep rising rapidly without reduction, leading to very high greenhouse gas levels.

What are global climate models? (1)

Global climate models are computer simulations that show how changes in emissions affect the climate (e.g. temperature).

How are global climate models used? (1)

Different emissions scenarios are put into these models to predict possible future outcomes.

Why might some models of climate change not be completely reliable? (3)

- Climate models may not include unpredictable factors like human efforts to reduce greenhouse gas emissions.

- There are limits to the computing power and equipment used.

- Some atmospheric phenomena are too complex for models to accurately reproduce.

What are the five main limitations of using extrapolated climate data to predict the future? (5)

- We don't know which emissions scenario will happen, so we can't be sure which prediction is most accurate.

- It's unclear how much warming each scenario will actually cause.

- We can't separate future changes from possible natural climate influences.

- We don't know how effective actions to reduce emissions will be.

- The complex feedback systems in the climate make predictions uncertain.

What are two ways scientists can share the results of an investigation? (2)

- Scientific journals

- Scientific conferences

What are scientific journals? (1)

Published articles reviewed by experts.

What are scientific conferences? (1)

Presentations and discussions with other researchers.

How does increasing temperature affect the rate of enzyme-controlled reactions? (3)

- As temperature increases, enzymes gain more kinetic energy, so molecules move faster and collide more often with substrates.

- The energy of collisions also increases, meaning more collisions result in successful reactions.

- This increases the overall rate of enzyme activity.

What happens to enzymes at very high temperatures? (3)

- High temperatures cause enzyme molecules to vibrate more.

- This vibration can break bonds that hold the enzyme's shape, changing the active site.

- The enzyme becomes denatured, so the substrate no longer fits and the enzyme stops working.

What is metabolism? (1)

Metabolism is the sum of all chemical reactions in a cell or organism, controlled by enzymes.

How can climate change affect development in temperature-sensitive species? (1)

Climate change can alter development by affecting temperature-sensitive processes such as sex determination in reptiles.

How do warmer temperatures affect metabolic reactions? (1)

Warmer temperatures speed up metabolic reactions, so organisms grow faster.

How does temperature affect life cycle completion? (1)

Higher temperatures can lead to faster development, so organisms may complete their life cycles more quickly.

Why do higher temperatures speed up growth and development? (1)

Enzymes involved in growth and development work more efficiently at higher temperatures, up to an optimum point.

How can rising temperatures disrupt reproduction or migration? (1)

Increasing temperatures can disrupt breeding or migration timings by disrupting seasonal patterns.

How do warmer temperatures affect microorganisms? (1)

Warmer temperatures increase their rate of multiplication, but if it becomes too hot, they may die.

What is one example of how global warming speeds up photosynthesis? (2)

- Plants have an optimum temperature for photosynthesis.

- Up to that point, higher temperature increases enzyme activity, so plants grow faster.

What happens when temperature gets too high for some organisms? (2)

- If the temperature rises too much, enzymes denature, slowing down metabolic reactions.

- This causes the organism to grow more slowly and complete its life cycle slower.

How does temperature affect egg development in cold water fish? (2)

- Eggs of cold water fish (like trout or salmon) only hatch at low temperatures.

- If the water temperature is too high, eggs won't hatch.

How can rising temperatures affect where species live? (1)

As temperatures rise, rainfall patterns and seasons may shift, causing species to move to areas that match their ideal environmental conditions.

How can species movement affect other organisms? (1)

Movement into new areas can lead to competition with other species, which may result in extinction for some.

What happens if species cannot move to suitable areas? (1)

If species cannot move, they may die out.

How can global warming expand a species' range? (1)

If new areas become suitable due to climate change, the range of a species may expand.

What are two examples of how species distribution has changed due to global warming? (2)

- Alpine plants have moved higher up mountains to find cooler conditions.

- European butterflies have shifted their range northwards from southern Europe.

How does global warming affect rainfall patterns? (2)

- Global warming causes changes in global rainfall patterns - some areas will receive more rain, while others will get less.

- These changes affect plant and animal life, depending on their tolerance to moisture levels.

How does changing rainfall patterns affect the life cycle of plants? (2)

- Organisms like desert plants (e.g. ocotillo) rely on rainfall to grow and reproduce.

- If rainfall is reduced, these plants may stay dormant for longer periods, slowing their life cycles.

How does changing rainfall patterns affect species distribution? (2)

- Reduced rainfall can make some areas, like deserts, expand.

- Species that aren't adapted to dry conditions may have to migrate or die out.

How are seasonal cycles changing due to global warming? (1)

Global warming is altering the timing of the seasons, such as making spring arrive earlier.

How do changes in seasonal cycles affect organisms? (2)

- Organisms are adapted to seasonal timing for food, reproduction, and temperature.

- If the seasons shift, they may experience mismatches in food availability or temperature, affecting their development.

Why may an increase in environmental temperature lead to a shorter life cycle? (3)

- The life cycle of an organism depends on metabolic reactions.

- An increase in temperature increases the kinetic energy of enzymes.

- This causes more frequent collisions between enzymes and substrates, resulting in a faster rate of formation of enzyme-substrate complexes, increasing the rate of metabolism.

How does changing seasonal cycles affect life cycles? (2)

- Some species, like red squirrels in Canada, are giving birth earlier than usual.

- This is due to earlier availability of food, which accelerates their development.

What is an example of how climate change has affected a species due to changing seasonal cycles? (3)

- Swallows migrate from South Africa to Europe in spring to breed.

- If spring starts earlier, flowers and insects appear before the swallows arrive.

- There is less food, so fewer chicks survive, and the swallow population may decline.