Increase in Greenhouse Gases (College Board AP® Environmental Science) : Study Guide

Issues with excess greenhouse gases

Is climate change the same as global warming?

• The simple answer is no, but they are related to each other

• Climate change is a long-term change in average temperatures and weather patterns that define local, regional and global climates, usually over a 30-year period

• Global warming is the rise of Earth's average surface temperatures because of the increasing concentrations of greenhouse gases in the atmosphere due to human activities such as burning fossil fuels

• The rise of global temperatures can and is changing global climates

• Therefore, excess greenhouse gases in the atmosphere leads to a variety of environmental, social and economic problems, including

  • melting ice sheets

  • ocean water expansion

  • rising sea levels

  • disease vector spreading

  • climate refugees

  • health impacts

  • infrastructure damage, etc.

The IPCC

• In 1988, a group of 3,000 scientists worked together to assess climate change. The IPCC (Intergovernmental Panel on Climate Change) was formed as a result

• The IPCC’s goal is to decide the potential environmental, social, and economic impact of climate change

• IPCC scientists have gained an understanding of how rising CO₂ causes temperature increases and its subsequent effect

Changing environment

Sea level rise

• Rising sea levels and flooding from melting polar ice caps, ice sheets, permafrost, and glaciers can damage coastal populations and ecosystems through erosion

• Meltwater flows faster overland into the oceans as temperatures rise, increasing rates of soil erosion

• Oceans expand as they warm

  • Warmer water takes up more space than colder water due to increased movement and vibration of water molecules

Disease vector spread

• Tropical diseases will spread to cooler regions as temperatures rise, as disease vectors, like mosquitoes and ticks, will survive and breed in warmer environments

  • Italy has experienced cases of malaria since 2017, when it was previously a malaria-free area

• Warming will affect the location, number and range of disease vectors (including insects, animals, plants or microbes)

  • This will increase disease transmission rates

• Changes in species distribution and numbers may disrupt ecosystems and increase disease outbreaks due to population density

Ocean acidification

• Climate change and ocean acidification are driven by rising atmospheric CO₂

  • Oceans absorb some of the excess CO₂ emitted by burning fossil fuels

  • The ocean becomes more acidic as dissolved CO₂ levels rise

• Ocean acidification reduces calcium availability, making it harder for corals and shellfish to form and maintain their shells and skeletons, which can lead to population decreases

• Acidification changes the food chain and marine community structure, affecting other species indirectly

• Increasing sea temperatures and ocean acidification have resulted in coral bleaching

Weather extremes and changes

• The relationship between extreme weather events and global warming is complex and it is difficult to link any single event directly to global warming

• However, droughts, heatwaves, flooding, and hurricanes are becoming more frequent and intense

  • Increasing global temperatures from higher levels of atmospheric greenhouse gases (from human activities) can change atmospheric and oceanic circulation patterns, which do affect extreme weather events

  • Higher temperatures increase the rate of evaporation, which worsens droughts

  • Increased water vapor in the atmosphere alters precipitation patterns and intensifies storms, rainfall, and hurricanes

Biodiversity loss

• Climate change can harm ecosystems and animals, reducing biodiversity levels

• As temperatures rise, many species may struggle to live and be forced to relocate

• If suitable habitats are unavailable or species cannot migrate or adapt fast enough, they may become extinct

• Warming can indirectly reduce biodiversity by affecting water availability, intensifying natural disasters, and spreading disease, causing species extinction

Changing society

• Climate change impacts human societies at various scales and socio-economic conditions

• This means that the impacts of climate change affect societies differently based on their:

  • economic status

  • resources

  • social conditions

• Socio-economic conditions include factors like:

  • income levels

  • access to resources

  • quality of infrastructure

  • education

  • healthcare availability

Air quality

• Higher temperatures can increase the formation of harmful ground-level ozone

• More frequent and severe wildfires release large amounts of smoke and particulate matter into the air

• Climate change can lead to more frequent stagnant air conditions, which prevent pollutants from dispersing

Heatwaves

• Heatwaves can increase in frequency and intensity, making them especially dangerous for the young and elderly

• Increased temperatures negatively affect people with cardiopulmonary diseases

• E.g. the North American Heatwave 2021:

  • A severe and prolonged heatwave hit the Pacific Northwest region of the United States and Western Canada in June 2021

  • The extreme heatwave led to

    • Hundreds of deaths across the region

    • Overwhelmed hospitals with cases of heat-related illnesses

    • Caused power outages as electrical grids struggled to cope with increased demand for air conditioning

Water supply impacts

• Longer and more severe droughts reduce water availability

• Melting glaciers reduce freshwater availability for downstream communities

• More intense rainfall and flooding events contaminate drinking water with pollutants, sewage and chemicals

• Warmer water temperatures can lead to algal blooms like those in Lake Erie in North America, which have repeatedly made the water unsafe for drinking

Agriculture impacts

• Changes in temperature and rainfall affect crop production

• Warmer climates increase the prevalence of agricultural pests

• Less reliable food supply and higher prices

• Heat stress affects livestock health and productivity

• Diets may be restricted by food shortages leading to malnutrition and famine

Infrastructure impacts

• More frequent hurricanes, floods and storms damage infrastructure

• Roads and railways damaged by extreme weather

• Increased costs for cooling with air conditioners

• Increased cost of repairs from storm damage

• Coastal erosion damages properties on seafronts

Settlements

• Settlements in low-lying areas may have to be abandoned or need additional defenses against sea level rise

• Moving settlements or improving flood defences will be costly

• Increased flooding due to sea level rise and increased frequency and severity of storms will lead to displacement of large numbers of people