BaCCC/Video Summaries/Earth's Climate System

Video Summary 1

2.1 Earth’s Climate System (14:02)

https://www.youtube.com/watch?v=nW-s8KXKlzQ&list=PLAHtWWrZTgn-i_U-ft6cjsTj2faylPSJO&index=2

• Our planet harbours life forms in every nook and cranny, setting us apart from our neighbouring planets.
• Rocks are important for climate, because they provide the bulk of this physical planet and they interact with the other parts.
• Rocks break down over time in a process called weathering, which takes carbon dioxide out of the atmosphere and decreases the greenhouse effect, while volcanoes spew rocks and gases from the Earth’s interior and add carbon dioxide back into the atmosphere.
• The atmosphere is dominated by 78% hydrogen gas, 21% oxygen gas, 1% argon gas and tiny amounts of other gases such as carbon dioxide, methane, ozone and more, called greenhouse gases.
• Of the gases in the atmosphere, the most important for climate are the greenhouse gases, which have chemical structures that let them interact with specific wavelengths of infrared radiation coming upwards from the Earth’s surface.
• Ozone in the stratosphere absorbs ultraviolet radiation from the sun.
• In contrast to Earth, Venus and Mars have atmospheres that have about 95% carbon dioxide.
• Venus’s atmosphere is very thick and has a super strong greenhouse effect.
• Mars’s atmosphere is thin. It, therefore, has a weak greenhouse effect and is very cold.
• Aerosols in the atmosphere reflect some of the sun’s energy back into space.
• Water, ice, clouds and water vapour are the primary important climate reservoirs in which water spends time on our planet.
• Life is one of the crucial components of the climate system.
• Living things exchange oxygen and carbon with the atmosphere; they participate in cycling nutrients, and more.
• In the oceans, life takes up and releases carbon.
• The oceans are currently becoming more acidic, getting ahead of the ocean’s buffering capacity.
• The ancient biosphere, which harvested solar energy back then, is the source of carbon for the fossil fuels we burn today.
• Humans are part of the biosphere too, and some of the things we do influence other parts.
• We have decreased biomass in some parts of the world through deforestation and clearing land for agriculture, and we have increased mass in other areas, either through the abandonment of cropland over which forests grew back or the deliberate planting of things.
• Life is not necessary for a planet to have a climate.
• Water, rocks, gases and life participate somehow in moderating the energy flows within the Earth’s climate system.
• The three big factors in energy flows are solar energy, Earth’s reflectivity and the greenhouse effect.
• Solar energy is the primary source of energy for the climate system.
• Reflectivity is about how much gets reflected back to space.
• The greenhouse effect is about how infrared radiation emitted by the Earth’s surface is absorbed and re-emitted by greenhouse gases, thereby slowing the passage of energy back to space.
• The atmosphere, hydrosphere, biosphere and geosphere [or lithosphere] comprise a useful way to describe the basic reservoirs for materials on Earth.
• Materials constantly exchange among these reservoirs.
• The reflection characteristics of the Earth’s materials in all four reservoirs influence how much solar energy reflects directly back to outer space.