Causes and Effects of Climate Change | National Geographic

Human activities from pollution to overpopulation are driving up the earth’s temperature and fundamentally changing the world around us.

The main cause is a phenomenon known as the Greenhouse Effect. Gases in the atmosphere such as water vapor, carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons let the sun’s light in but keep some of the heat from escaping like the glass walls of a greenhouse. The more greenhouse gases in the atmosphere, the more heat gets trapped, strengthening the greenhouse effect and increasing the earth’s temperature.

Human activities like the burning of fossil fuels have increased the amount of CO2 in the atmosphere by more than a third since the Industrial Revolution. The rapid increase in greenhouse gases in the atmosphere has warmed the planet at an alarming rate. While Earth’s climate has fluctuated in the past, atmospheric carbon dioxide hasn’t reached today’s levels in hundreds of thousands of years.

Climate change has consequences for our oceans, our weather, our food sources, and our health. Ice sheets such as Greenland and Antarctica are melting. The extra water that was once held in glaciers causes sea levels to rise and spills out of the oceans, flooding coastal regions. Warmer temperatures also make weather more extreme.

This means not only more intense major storms, floods, and heavy snowfall but also longer and more frequent droughts. These changes in weather pose challenges. Growing crops becomes more difficult, the areas where plants and animals can live shift, and water supplies are diminished. In addition to creating new agricultural changes, climate change can directly affect people’s physical health.

In urban areas, the warmer atmosphere creates an environment that traps and increases the amount of smog. This is because smog contains ozone particles which increase rapidly at higher temperatures. Exposure to higher levels of smog can cause health problems such as asthma, heart disease, and lung cancer.

While the rapid rate of climate change is caused by humans, humans are also the ones who can combat it. If we work to replace fossil fuels with renewable energy sources like solar and wind, which don’t produce greenhouse gas emissions, we might still be able to prevent some of the worst effects of climate change.

• Human activities /ˈhjuːmən ækˈtɪvətiz/ (n) – Actions performed by humans that affect the environment.
  SYN: human actions, human behavior
  Example: Human activities such as deforestation contribute to global warming.

• Overpopulation /ˌoʊvərˌpɑːpjəˈleɪʃn/ (n) – When there are too many people in an area for the available resources.
  SYN: overcrowding, population explosion
  Example: Overpopulation in cities can lead to housing shortages.
• Phenomenon /fəˈnɑːmənɑːn/ (n) – A fact or event that can be observed, especially one that is unusual.
  SYN: event, occurrence
  Example: Climate change is a global phenomenon that requires urgent attention.
• Greenhouse effect /ˈɡriːnˌhaʊs ɪˈfekt/ (n) – The trapping of heat in the Earth’s atmosphere by greenhouse gases.
  SYN: global warming, climate warming
  Example: The greenhouse effect is causing the Earth’s temperature to rise.
• Fossil fuels /ˈfɑːsl ˈfjuːəlz/ (n) – Natural fuels like coal, oil, or gas formed from the remains of living organisms.
  SYN: coal, oil, natural gas
  Example: Burning fossil fuels releases carbon dioxide into the atmosphere.
• Industrial Revolution /ɪnˈdʌstriəl ˌrevəˈluːʃn/ (n) – The period when industries grew rapidly and machines replaced manual labor.
  SYN: industrialization, industrial age
  Example: The Industrial Revolution greatly increased carbon emissions.
• At an alarming rate /æt æn əˈlɑːrmɪŋ reɪt/ (adv) – Very quickly and causing worry.
  SYN: rapidly, worryingly fast
  Example: Ice sheets are melting at an alarming rate due to climate change.
• Fluctuate /ˈflʌktʃueɪt/ (v) – To change frequently in size, amount, or level.
  SYN: vary, oscillate
  Example: Temperatures can fluctuate greatly in the desert.
• Carbon dioxide /ˌkɑːrbən daɪˈɒksaɪd/ (n) – A gas produced by burning carbon and living organisms breathing.
  SYN: CO2, carbon emissions
  Example: Plants absorb carbon dioxide during photosynthesis.
• Spill out of /spɪl aʊt əv/ (phrasal verb) – To flow or escape from a container or place.
  SYN: overflow, leak
  Example: Water spills out of the ocean during flooding.
• Droughts /draʊts/ (n) – Long periods with little or no rain, causing water shortages.
  SYN: dry spells, water scarcity
  Example: Prolonged droughts have affected agriculture in many regions.
• Pose challenges /poʊz ˈtʃælɪndʒɪz/ (v phrase) – To create problems or difficulties.
  SYN: create obstacles, present difficulties
  Example: Climate change poses challenges to food security.
• Diminish /dɪˈmɪnɪʃ/ (v) – To become smaller or less important.
  SYN: reduce, decrease
  Example: Forest cover has diminished due to illegal logging.
• Agricultural changes /ˌæɡrɪˈkʌltʃərəl ˈtʃeɪndʒɪz/ (n phrase) – Alterations in farming practices or production.
  SYN: farming transformations, crop adaptations
  Example: Agricultural changes are necessary to adapt to new weather patterns.
• Ozone particles /ˈoʊzoʊn ˈpɑːrtɪklz/ (n) – Small amounts of ozone found in the air.
  SYN: ozone molecules, air pollutants
  Example: High levels of ozone particles contribute to smog.
• Asthma /ˈæzmə/ (n) – A condition where breathing becomes difficult due to inflamed airways.
  SYN: respiratory condition, breathing disorder
  Example: Asthma attacks can be triggered by high pollution levels.
• Combat /ˈkɑːmbæt/ (v) – To fight against something harmful.
  SYN: fight, battle
  Example: Efforts to combat climate change include reducing carbon emissions.
• Renewable energy sources /rɪˈnuːəbl ˈɛnərdʒi ˈsɔːrsɪz/ (n) – Energy from natural resources like wind or solar power.
  SYN: sustainable energy, green energy
  Example: Using renewable energy sources can help lower pollution.

• Produce greenhouse gas emissions /prəˈduːs ˈɡriːnhaʊs ˈɡæs ɪˈmɪʃənz/ (v phrase) – To release gases that trap heat in the atmosphere.
  SYN: emit CO2, release carbon emissions
  Example: Factories that burn coal produce greenhouse gas emissions.