Warm Up: 2-21 What are the impacts of climate change on humans?

What are greenhouse gases? (GHG) Gas in the atmosphere that absorbs and emits radiation Primary GHG’s in Earth’s Atmosphere: Carbon Dioxide Methane(biological processes) Nitrous Oxide (fertilizer/nitrogen)

What effects do GHG’s have on the Earth? Trap heat in the atmosphere, which makes the Earth warmer. 3 main factors that determine a gas’s effect on climate change: How much? How long? How powerful? Carbon dioxide is the mot important greenhouse gas emitted by humans.

Greenhouse Effect Greenhouse gases keep the Earth warm through a process called the greenhouse effect.

Fossil Fuels Fossil fuels are hydrocarbons, primarily coal, fuel oil or natural gas, formed from the remains of dead plants and animals. We rely on fossil fuels for our energy needs. When we burn fossil fuels it releases carbon dioxide, a heat trapping gas, into the atmosphere.

Carbon Cycle What is Carbon? An element found in all living things. A component of carbon dioxide (important gas in the Earth’s atmosphere). Carbon in our atmosphere occurs as carbon dioxide (CO2) and is one of the main gases linked to climate change. It remains in the atmosphere a long time, causing temperatures on Earth to rise. Respiration: (release of energy) Sugar + oxygen  CO2 + water + energy (to do work) Photosynthesis: Water + CO2 + solar energy  sugar + oxygen Plants absorb CO2 from the atmosphere during photosynthesis and release CO2 into the atmosphere during respiration. The oceans surface layer holds large amounts of dissolved organic carbon that is exchanged with the atmosphere.

Carbon Cycle

Signs of Climate change Scientists look at: Historical records Collect measurements and observe Trends in temperature Weather patterns Sea level Because there are so many clues from all over the world, we know that climate change is already happening today.

Impacts of global warming Higher temperatures: GHG’s are trapping more heat in the atmosphere, which is causing average temperatures to rise all over the world. Temperatures have risen over the last 30 years, and 2000-2009 was the warmest decade ever recorded. As the earth heats up, heat waves are becoming more common. Why does it matter? Higher temperatures mean that heat waves are likely to happen more often and last longer. Warmer temperatures can also lead to a chain reaction of other changes around the world. Increasing air temperatures also affect the oceans, weather patterns, snow, ice and plants and animals. The warmer it gets, the more severe the impacts on people and the environment will be.

Impacts of global warming More droughts: A drought is an extended period of dry weather caused by a lack of rain or snow. As temperatures rise, more moisture evaporates from land and water, leeaving less water behind. Since the 1970s droughts have become longer and more extreme worldwide, particularly in the tropics and subtropics. Droughts are expected to get longer and more severe. Why does it matter? A drought means there is less water available for drinking, watering crops, making electricity and hydroelectric dams and other uses.

Impacts of global warming Melting Glaciers: glaciers are large sheets of snow and ice that are found on land all year long. Warmer temperatures cause glaciers to melt faster than they can accumulate new snow. Over the last 50 years glaciers all over the the world have been melting, and the rate of melting has been speeding up. As glaciers and the giant ice sheets on Greenland and Antarctica melt, they add more water to the ocean causing sea-level to rise.

Impacts of global warming Rising sea level: As water gets warmer, it takes up more space. Sea level is also rising due to melting glaciers and ice sheets. Over the past 100 years, the average sea level around the world rose by 7 inches. Why does it matter? Rising sea level is a threat to people who live near the ocean. Low lying areas will have more frequent flooding, and very low lying land could be submerged completely. Rising sea level can also harm important coastal ecosystems.

So, What can we do to slow down global warming? Fuel Efficient Cars (when less gasoline is burned, less carbon dioxide ends ups in the atmosphere) Energy-efficient buildings (Energy Star) Nuclear Energy (Splitting uranium atoms apart to make electricity) Wind Energy (wind turbines to make electricity) Geothermal Energy: Geothermal power plants use heat from deep inside the Earth to generate steam to make electricity. Geothermal heat pumps tap into heat close to Earth’s surface to heat water or provide heat for buildings. Solar Energy: A photovoltaic cell absorbs light and converts it directly into electricity.

Nuclear Energy

Wind turbines

Geothermal Power Plants

Geothermal heat pump

Solar panels