- Earth is known as the Goldilocks planet as it is ‘just right’ for habitation (not too hot, not too cold). There is no known life on any other planet in our solar system. Earth is also known as the blue planet as the majority of the surface is ocean. Earth’s ‘atmosphere’ is vital for sustaining life. The atmosphere is a huge blanket of gases – mostly oxygen and nitrogen.
- We are living in what’s known as the Anthropocene Era. This denotes the current geological age, during which human activity is the dominant influence on climate and the environment.
- Human activities have increased carbon dioxide and other greenhouse gas emissions, driving up temperatures.
- Scientists say temperatures are now rising faster than at any other time in history. This is linked to the greenhouse effect, which describes how the Earth’s atmosphere traps some of the Sun’s energy. Solar energy radiating back to space from the Earth’s surface is absorbed by greenhouse gases and re-emitted in all directions.
- Scientists believe we are adding to the natural greenhouse effect, with gases released from industry and agriculture trapping more energy and increasing the temperature.
- This is known as climate change or global warming.
- Most emissions of CO2 come from burning fossil fuels. When carbon-absorbing forests are cut down and left to rot, or burned, that stored carbon is released, contributing to global warming.
- Since the Industrial Revolution began in about 1750, CO2 levels have risen more than 30%. The concentration of CO2 in the atmosphere is higher than at any time in at least 800,000 years.
- Other greenhouse gases such as methane and nitrous oxide are also released through human activities but they are less abundant than carbon dioxide.
What is the evidence for global warming?
- The world is about one degree Celsius warmer than before widespread industrialisation, the World Meteorological Organization (WMO) says.
- The 20 warmest years on record all occurred in the past 22 years, with 2015-18 making up the top four. 2020 is set to be a record-breaker.
- Across the globe, the average sea level increased by 3.6mm per year between 2005 and 2015. Most of this change was because water increases in volume as it heats up. However, melting ice is now thought to be the main reason for rising sea levels. Most glaciers in temperate regions of the world are retreating.
- Satellite records show a dramatic decline in Arctic sea-ice since 1979. The Greenland Ice Sheet has experienced record melting in recent years.
- Satellite data also shows the West Antarctic Ice Sheet is losing mass. A recent study indicated East Antarctica may also have started to lose mass.
- The change in the global surface temperature between 1850 and the end of the 21st Century is likely to exceed 1.5C, most simulations suggest.
- Temperature rises of 2C had long been regarded as the gateway to dangerous warming.
What will happen in the future?
- No-one is sure, but the effects could be catastrophic. The ice in glaciers and the ice in the polar regions could melt and sea level would rise. This would flood low-lying areas such as Bangladesh, and coral islands in the Pacific Ocean.
- If animals and plants are unable to move to a new place or adapt to new climatic conditions, they could die out. This has already happened to the Costa Rican golden toad.