Human Impact on the Carbon Cycle and The Albedo Effect page 52

Human Impact on the Carbon Cycle Mining Fossil Fuels by mining and burning fossil fuels (petroleum, natural gas, oil) we are returning the stored carbon back into the atmosphere faster than normal Clearing Vegetation by clearing vegetation (deforestation, agriculture, urbanization) we are decreasing the amount of carbon removed from the atmosphere through photosynthesis

A) The Greenhouse Effect 1. Shorter wavelength of sunlight enter the greenhouse 2. Light is reflected and wavelengths become longer 3. The longer wavelengths are trapped by the glass This is the same thing that happens to the Earth, only instead of glass trapping the long wavelengths of light and heat it is the greenhouse gasses (CO2, CH4)

B) Global Warming The burning of wood and fossil fuels ( coal, oil, and gas) has caused carbon dioxide levels to triple over the last 40 years

Greenhouse Effect

C) A Warmer Climate Problems arising from increasing temperatures include; decrease in permafrost snowcaps and glacier melting – increased lake and river levels, possible flooding desertification – the amount of dry desert land increases

The Albedo Effect Albedo – is a measure of how reflective a surface is - high albedo mean the surface reflects a lot of light - low albedo means the surface reflects very little light

The Albedo Effect cont . . . . . . . Snow and ice have a very high abledo (very reflective) If snowcaps and glacier melt, less light will be reflected (more absorbed) and the temperature of the Earth will increase even more Disrupting the snow-temperature feedback cycle

Equilibrium and Earth’s Atmosphere The Earth once contained extremely high levels of carbon dioxide, causing the planet to warm Microscopic marine life (stromatolites) then began to consume the carbon dioxide and release methane (CH4) (3.5 billion years ago) The large amounts of methane caused the planet to warm further, increasing the populations of methane producing bacteria

Equilibrium and Earth’s Atmosphere Warm temperatures intensified the water cycle and the weathering of rocks Eventually the methane caused a cloud around the Earth blocking some sunlight and decreasing the temperature New cooler temperatures allowed for new photosynthetic bacteria to develop Oxygen producing bacteria took over causing oxygen levels to increase