Unit 2 - The consequences of global climate change Flashcards
what are the effects on the natural, social and economic environment of global warming?
Rise in sea levels, causing flooding in low-lying areas such as the Maldives and Kiribati
Increase in storm activity
Change in agricultural patterns
Rainfall over the USA, southern Europe, and the Commonwealth
Up to 40 per cent of wildlife species will become extinct
Hydrosphere
all the waters on the Earth; including freshwater, seawater and ice/glaciers
what are the impacts of climate change on the hydrosphere?
More frequent extreme weather events
Decrease in annual precipitation in mid-latitudes and dry regions
Increase in annual precipitation in high latitudes and wet regions
what are the changes in sea ice?
Ever since 1975, the Arctic sea ice has declined dramatically. Its overall volume, thickness and extent have been declining for decades.
The time the ice remains is changing.
Example: in 1988, ice that was more than four years old accounted for over one-quarter of the Arctic sea ice, but by 2013 it was less than one-twelfth.
The Arctic is believed to be at its warmest in the last 40,000 years.
what are the impacts of climate change on glaciers and ice caps?
Many Himalayans glaciers are retreating
The region’s water supply (Hindu Kush Himalayan region) would decrease - this would affect 1.5 billion people
Alter streamflow characteristics in many basins
what are the implications of changes in the water stored in ice and oceans?
Increase in methane emissions - methane is released from the tundra because of the release of chlorine atoms.
Increase in extreme weather events
Increase in the potential for wave formation
Affect polars bears - they have less time to hunt and must spend more time on land → their diets have become less nutritious
Why and how have the sea levels change?
By 2100, sea level is predicted to have risen between 40 cm and 80 cm due to thermal expansion of the oceans and melting of snow and ice.
What are the impacts of changing sea levels?
an increased risk of flooding, which could potentially impact the 40% of the world’s population that is living within 100km of a coastline. Such coastal flooding could lead to:
Damage to infrastructure, homes and industry, leading to loss of livelihood
Risk to human life, such as death from drowning
Salinisation of agricultural land, reducing its capacity to grow many types of crops
Contamination of freshwater resources by salt water, including saline intrusion of groundwater resources: this would render fresh water too salty for domestic, agricultural and industrial uses
Degradation of coastal ecosystems such as wetlands, estuaries, mangroves and beaches
Damage to inland ecosystems, threatening wildlife.
How have the levels of carbon stored in ice, oceans and the biosphere change?
Before the Industrial Revolution, the amounts of ice were relatively balanced. However, human activity have tipped off this balance.
Most of the Earth’s carbon is stored in rocks, but most are unavailable due to their slow rate of turnover.
The rest of the carbon is stored in the atmosphere (2%), biomass (5%), fossil fuels (8%) and the oceans (85%).
How have the levels of carbon stored in ice change?
Carbon stored in ice and permafrost is being released as permafrost begins to thaw.
- Increases the net productivity in periglacial environments.
- Increased methane emissions
- Decreased snow reduces the reflectivity on the surface, increasing the absorption of solar radiation
How have the levels of oceans stored in ice change?
The ocean helped the atmosphere absorb the CO2. But recently, due to human activity, the rate of CO2 has risen significantly, effectively rising the amount of CO2 in the ocean as well. The effects include:
Acidification of water - endangers marine life
Since the 1970, the oceanic pH has dropped by 0.1, a 30 per cent change in acidity.
Shell-building organisms such as crabs, lobsters and coral end up with thinner shells.
Increase in temperature of the water - decrease the abundance of phytoplanktons
How have the levels of oceans stored in the biosphere change?
Atmosphere:
Human activities have been increasing the volume of carbon dioxide
This destroys the ozone layer that blocks harmful ultraviolet rays.
Hydrosphere:
Brings disorder to the aquatic environment
Lithosphere:
Terrestrial plants have absorbed approximately 25% of the carbon dioxide that humans have released into the atmosphere.
Soils are important carbon sinks and contain about 75 per cent of land-based carbon.
Carbon can leave soil through soil respiration which releases carbon dioxide, or by erosion which carries carbon dioxide into the hydrosphere
Example: many Canadian forests were sinks, converting carbon dioxide through photosynthesis into biomass
How have the weather patterns and rainfall change?
200 million people at risk of being driven from their homes by flood or drought by 2050
An increase in storm activity such as more frequent and intense hurricanes
Reduced rainfall leading to severe drought
Up to 4 billion people suffering from water shortages if temperatures rise by 2 degrees.
How have biomes change as a result of climate change?
Biomes will move up slopes such as mountains due to climate change
Low-lying biomes (mangroves) will most likely be lost due to changes in sea level.
Rapid changes in the environment do not allow for species to adapt
Some will migrate to new areas that offer the conditions that they need
Some will face extinction
Reduction in biodiversity as they change their distribution
Species in high-altitude and high-latitude will have fewer options for migration and more at risk of becoming endangered
Up to 40 per cent of species could become extinct if temperatures increase by 2 degrees.
How have crops change as a result of climate change?
Increase in mid- to high-latitude regions
Decrease in low-latitudes regions
Example: If temperature increases by 3 degrees, there will be a 35 per cent drop in crop yields across Africa and the Middle East.
Extreme precipitation and temperature events can reduce crop growth, dry out plants (drought) or wash them away completely (floods)
Seasonal shifts in temperature range can cause significant problems for fruit crops.
Example: An early thaw in spring causes early budding and flowering and a return to ‘normal’ temperatures kills the delicate flowers. Warm winters caused US$220 million in damage to cherry crops in Michigan.
Higher summer temperatures cause heat stress in crops and make the soil dry. Irrigation is possible in some areas but the risk of salinisation is increased as higher temperatures increase evaporation.
Growth of weeds, pests and fungi - result in some diseases spreading from low to mid-latitudes
