Human activities have changed the environment on a global scale. We will learn about problems such as global warming, air pollution, water pollution, acid rain, and ozone-layer depletion, as well as efforts to address them.
Basic Knowledge
Global warming: A phenomenon in which Earth's average temperature rises because of an increase in greenhouse gases(carbon dioxide CO₂・methane CH₄・CFCs, and others) in the atmosphere.
Causes: Large-scale consumption of fossil fuels(oil・coal・natural gas) and deforestation.
Effects: Rising sea levels, abnormal weather, changes in ecosystems, and agricultural damage.
Acid rain: Rain becomes acidic with a pH of 5.6 or lower when sulfur oxides SOx・nitrogen oxides NOx dissolve in the atmosphere. It causes forest death, extinction of fish in lakes, and corrosion of buildings.
Ozone-layer depletion: CFCs used in refrigerators and sprays destroy the ozone layer, making it easier for harmful ultraviolet rays to reach the ground. CFCs were regulated by the Montreal Protocol(1987).
Air pollution: Exhaust gases from factories and automobiles(NOx、PM2.5, and others)→respiratory diseases.
Water pollution: Industrial wastewater and domestic wastewater→red tides and algal blooms. An increase in nitrogen and phosphorus causes eutrophication.
Four major pollution-related diseases(in Japan during the period of rapid economic growth):
① Minamata disease(Kumamoto・Niigata): Organic mercury poisoning by methylmercury
② Itai-itai disease(Toyama): Cadmium poisoning
③ Yokkaichi asthma(Mie): Sulfur dioxide from factories
④ Niigata Minamata disease(Niigata): Methylmercury
Global warming（A phenomenon in which average temperature rises because of increased greenhouse gases）
Greenhouse gases（CO₂・CH₄・CFCs・water vapor, and others; CO₂ is representative）
Acid rain（Rain with a pH of 5.6 or lower caused by dissolved SOx・NOx）
Ozone-layer depletion（CFCs destroy stratospheric ozone, causing ultraviolet-ray damage）
Eutrophication（An increase in nitrogen and phosphorus that causes red tides and algal blooms）
SDGs（Sustainable Development Goals; adopted by the United Nations in 2015, with 17 goals）
Further Study (Background・Significance)
Carbon neutrality: The idea of making the difference between emitted CO₂ and absorbed or removed CO₂ equal to zero. Japan has also made an international pledge for carbon neutrality by 2050.
Specific measures:
① Shift to renewable energy(solar・wind・hydroelectric・geothermal・biomass).
② Energy conservation(LEDs・insulation・energy-efficient appliances).
③ Promote electric vehicles and hydrogen vehicles.
④ Absorb CO₂ through forest conservation and tree planting.
International efforts:
・Kyoto Protocol(1997): Required developed countries to reduce greenhouse gases.
・Paris Agreement(2015): All countries submit reduction targets, aiming to keep warming within +1.5℃〜2℃ above preindustrial levels.
・IPCC(Intergovernmental Panel on Climate Change): An international organization that provides scientific assessments.
3R: Reduce・Reuse・Recycle. The actions of each of us contribute to solving global-scale problems.
SDGs(Sustainable Development Goals, United Nations 2015): Of the 17 goals, Goals 6(water), 7(energy), 12(Responsible Consumption and Production), 13(climate action), 14(oceans), and 15(Life on Land) are related to the environment.
Building a sustainable society that balances environmental protection and economic development is a challenge for all of us living today.
- Global warming=increased greenhouse gases(CO₂ is representative)
- Acid rain=SOx・NOx, pH5.6 or lower
- Ozone-layer depletion=CFCs, Montreal Protocol(1987)
- Eutrophication=excess nitrogen・phosphorus→red tides・algal blooms
- Four major pollution-related diseases=Minamata・Niigata Minamata・Itai-itai・Yokkaichi asthma
- Carbon neutrality=zero difference between emissions and absorption
- Kyoto Protocol(1997)→Paris Agreement(2015)
- 3R=Reduce・Reuse・Recycle, SDGs
Points to Note (Easily Confused)
① Global warming(greenhouse gases) and ozone-layer depletion(CFCs) are different problems. Their causes and effects also differ. ② The pH of acid rain is 5.6 or lower(normal rain is also weakly acidic, with a pH of 5.6, because of CO₂). ③ Causes and locations of the four major pollution-related diseases: Minamata=methylmercury=Kumamoto, Itai-itai=cadmium=Toyama, Yokkaichi asthma=sulfur dioxide=Mie, Niigata Minamata=methylmercury=Niigata. ④ Distinguish the Kyoto Protocol(1997, developed countries only) from the Paris Agreement(2015, all countries).
Practice
- Give one representative example of a gas that is a major cause of global warming.
- Name the substance that destroys the ozone layer.
- Among the four major pollution-related diseases, what is the name of the disease caused by methylmercury that occurred in Kumamoto Prefecture?