Unit 2: Changing Climate

Hydrosphere: the areas of the planet containing water in three forms: gas, solid, and liquid.

Biosphere: the layer of the planet in which organisms can live, meaning the land, the sea and the atmosphere.

Atmosphere: a layer of gases held to the earth's surface by gravity.

Influence of Climate Change on the Biosphere:

• Higher global temperatures increase evaporation, reducing freshwater availability and harming vegetation growth, while melting permafrost allows new vegetation to grow in previously inhospitable areas, increasing biodiversity in polar regions.

• Rising temperatures melt icecaps, threatening the habitats of animals like polar bears.

• More frequent extreme weather events, such as cyclones, increase the risk of damage to coastal areas.

Interdependence between the Hydrosphere and the Atmosphere:

• Warmer temperatures allow air to hold more water vapour.

• Increased evaporation reduces Earth's surface water, potentially leading to insufficient precipitation to replenish freshwater stores.

• Rising sea temperatures, alongside global temperatures, enable oceans to store more carbon.

Reasons for Sea Level Rise:

• Thermal expansion: As ocean temperatures rise, water expands, increasing sea levels.

• Melting of land-based ice: The melting of glaciers and ice sheets adds water to the oceans, surpassing the evaporation rate.

Economic Consequences of Melting Ice:

Potential Benefits from greater land available:

• Agricultural development for arable or pastoral farming.

• Construction of factories and infrastructure, boosting employment, tax revenue, and GDP.

• Mining of minerals for trade, increasing employment and GDP.

• In the short term, it will provide fresh water for downstream communities and support irrigation and crop yields.

Economic Problems from Rising Oceans:

• Coastal flooding may result in the loss of homes, industries, and infrastructure, leading to significant economic losses in property and employment.

How Melting Polar Ice Will Affect Ocean Currents:

• Melting polar ice alters ocean temperature and salinity, disrupting thermohaline circulation, or the Global Ocean Conveyor.

• The influx of freshwater decreases the salt level and density of the North Atlantic Ocean, preventing water from sinking and circulating through the deep ocean.

• Disruption of the Global Ocean Conveyor will affect warmer oceanic currents, such as those in the North Atlantic, leading to cooling in Western Europe.

Climate Change’s Effect on Carbon Stores:

• Increased carbon dioxide in the atmosphere may boost plant growth.

• Wildfires, caused by reduced precipitation, release carbon dioxide into the atmosphere instead of being stored in the geosphere through decomposition.

• As carbon sinks, oceans will absorb more anthropogenic carbon dioxide from the atmosphere.

Consequences of Melting Permafrost:

• Melting permafrost releases methane and carbon dioxide, which are greenhouse gases that exacerbate global climate change.

• Roads and infrastructure may be damaged due to loss of stability.

• Landslides can occur, potentially affecting nearby communities and freshwater movement within drainage basins.

• Sediment released from melting permafrost can disrupt aquatic ecosystems.

• Contaminated soil may release toxins, leading to diseases like anthrax.

Ocean acidification: a reduction in the pH of the ocean caused by an increase in the amount of carbon stored in the oceans.

Consequences of Ocean Acidification:

• Ocean acidification contributes to rising global temperatures, as oceans absorb 90% of longwave radiation, forming carbonic acid.

• Marine ecosystems are disrupted; species that rely on carbonate for shells and skeletons are affected as carbonate decreases with acidity. Weaker shells dissolve, and coral skeletons dissolve faster than they can form.

• Coral bleaching also occurs due to rising temperatures impacting algae, which provide food, energy, and colour for corals.

• Commercial and subsistence fishing are impacted by weakened food chains, negatively affecting food security, employment, and GDP.

Drought: an extended period of unusually dry weather with insufficient rainfall.

How Climate Change Exacerbates Drought:

• Higher temperatures increase evaporation from surface water, soil, and vegetation, leading to drier conditions on land.

• This results in a global increase in the frequency and duration of droughts.

• In mid-latitude regions, longer dry periods are followed by shorter, more intense rainfall events.

Biome: a region of the world with a large, distinct, biological community that has developed as a response to shared physical, geographical and climatic characteristics.

Desertification: the process of land turning into desert.

How Climate Change Affects Desertification:

• Rising temperatures increase droughts and reduce regular rainfall, making it harder for vegetation to survive.

• People will need to search further for firewood and food for their animals, further depleting vegetation in the region.

• Reduced vegetation leads to less carbon dioxide absorption, causing more carbon dioxide to remain in the atmosphere, exacerbating global climate change.

How Global Climate Change has affected animal migration:

• towards the poles where it is cooler;

• higher up mountains where it is cooler;

• towards the equator where it is wetter

The Effect of Glaciers Melting on Agricultural Yields:

Short-Term Benefits:

• Increased meltwater provides more crop irrigation and ensures animal pasture availability, boosting agricultural yields.

• Surplus water can be stored during dry seasons when water is scarce.

Long-Term Costs:

• Over time, the glacier will no longer supply meltwater, leaving no freshwater source for agriculture.

• Farmers may face challenges with rich sediment carried by meltwater or difficulty predicting the amount of water available for irrigation.

Vector-borne diseases: diseases spread by insects, e.g. Malaria.

Water-borne diseases: diseases spread by consuming water containing bacteria and chemicals, e.g. Cholera.

Climate Change Impacts on Vector-Borne Diseases:

• Warmer temperatures allow vectors to spread to northern and southern latitudes and higher altitudes, increasing disease transmission.

• Higher temperatures accelerate the development of viruses within vectors and extend breeding seasons.

• Extreme weather events like cyclones and floods provide ideal breeding grounds for vectors.

Climate Change Impacts on Water-Borne Diseases:

• Warmer temperatures can expand the spread of diseases like cholera.

• Increased temperatures encourage more people to use water for recreation (e.g., swimming), potentially increasing exposure to pathogens.

• Extreme weather events disrupt water and sanitation systems, allowing bacteria to contaminate water supplies.

Why Climate Change Could Attract People to a Place:

• Shifting from a polar to a more temperate climate could make a region more appealing.

• The development of primary and secondary industries in areas that were once permafrost zones could attract people seeking new jobs.

• Melting polar ice opens up new transportation routes and ports, attracting workers to these emerging areas.