D4.3 Climate change

What is anthropogenic climate change?

It is climate change caused by humans / man-made

This is primarily done through combustion of fossil fuels, live stock (methane).

What is the correlation between carbon dioxide and temperature?

As carbon dioxide increases, temperature increases as well. There is a correlation, but also a causation.

What does the keeling curve show?

It shows the carbon dioxide concentration in the atmosphere over time, displaying that CO2 concentration is higher in the winter than in summer.

Why is there a greater carbon dioxide concentration in winter?

Because there is a decrease in photosynthesis in plants

What does positive feedback cycle mean in global warming?

Where an initial change is amplified, and global warming increases.

How is loss of snow and ice a positive feedback cycle?

Due to high temperatures, snow and ice melts into the oceans. The increased dark body of water decreases the albedo effect and even more heat is absorbed. This causes the temperatures to increase further.

How is decomposition of permafrost a positive feedback cycle?

When temperatures are high, permafrost melts. The gases that have been present in the decomposed bodies of dead animals, such as methane, are released into the atmosphere, heating temperatures further.

How is the release of carbon dioxide from the deep ocean a positive feedback cycle?

As temperatures increase, the ocean can act less as a sink as its ability to absorb CO2 decreases (as warm water has less capability to hold dissolved CO2). Carbon dioxide is released from oceans back into the atmosphere when they heat up.

How are forest fires a positive feedback cycle?

They release carbon dioxide into the atmosphere, which increases global temperatures as well, makes the land more dry, and causes more forest fires to occur.

How have boreal forests changed from carbon sinks to carbon sources?

They used to be a carbon sink, where carbon was stored in the ground.

• Warmer temp and less snowfall —> more droughts and less water —> less photosynthesis —> less CO2 absorbed

• Droughts —> brown and dry leaves —> more likely for a wildfire to occur

How are polar animals affected by the melting of ice?

• Their breeding spots melt, so less reproduction

• Rest on ice caps and foes in between hunting → become more exhausted and are undernourished → travel longer distances to access their food

What is nutrient upwelling?

It is when nutrient-rich water rises from the bottom of oceans to the surface. This occurs due to blowing winds that create currents. The nutrients encourage phytoplankton growth on the surface, which provides a habitat for aquatic animals.

How has nutrient upwelling decreased due to global warming?

As the oceans get warmer, the warmer surface of the water causes less wind to blow it away and allow the cold water to rise with the nutrients, thus prevent the aquatic ecosystem of phytoplankton to form.

What are upslope range shifts?

When organisms move upward to higher altitudes where it is cooler, to escape the warm weather.

E.g., the birds in new guinea are moving from forests to mountains

What are poleward range shifts?

When organisms move further north, toward the poles, to a cooler habitat

E.g., the sugar maple trees are moving to north america

How are coral reefs negatively impacted by climate change?

• Ocean acidification - due to harsh chemicals

• Coral bleaching - due to higher temperatures in water

What is ocean acidification in coral reefs?

More carbon dioxide is diffusing into the oceans, which forms carbonic acid and reduces the pH of oceans. The carbonate ions decrease, which are used by corals to build exoskeletons, so corals become weaker and have limited growth

What is coral bleaching in coral reefs?

Corals have a mutualistic relationship with algae, which are responsible for its colour. The increasing ocean temperatures stress coral and they release the algae and are bleached. They are not dead yet, but they have lost their source of food.

What is the negative impact of coral bleaching and acidification?

• Coral can no longer provide hiding places and shelter for aquatic organisms, leading to their extinction

What is carbon sequestration?

It is the process of capturing and storing atmospheric carbon dioxide

What are the methods in which carbon can be sequestered?

• Afforestation - plant trees because they absorb carbon

• Restoration of peat wetlands - carbon remains sequestered in the soil, and they are carbon sinks