Climate Change

The planet’s average surface temperature has risen about 1 The planet’s average surface temperature has risen about 1.4 degrees Fahrenheit since the late 1880s. Two-thirds of that warming has occurred since 1975.

Global Warming vs Climate Change Global warming refers only to the Earth’s rising surface temperature Climate change includes warming and the “side effects” of warming—like melting glaciers, heavier rainstorms, more frequent drought, increased fires, changes to the jet stream

What causes Earth’s climate to change? Changes in the atmosphere Natural processes Volcanoes Tectonic plate movement Changes in the sun Variability in Earth’s orbit every 20,000 – 100,000 yrs Human activities – any activity that releases “greenhouse gases” into the atmosphere

Example of the Greenhouse Effect If there were no greenhouse effect, Earth’s average temperature would be about 60°F colder. The Sun’s energy passes through the car’s windshield. This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up.

The Greenhouse Effect Fossil fuels (coal, oil, natural gas) Carbon Dioxide (CO2) Fossil fuels (coal, oil, natural gas)

Earth has experienced climate change before. We’ve had ice ages and interglacials (warm periods) on 100,000 year cycles for at least the last million years Warming episodes were triggered by the amount of sunlight reaching Earth as our orbit fluctuated. As the oceans warmed, they would release carbon dioxide (kind of like the fizz escaping a warm soda).

Over the last 50 years, solar forcing (how much radiation we receive from the sun) and volcanoes should have contributed to Earth cooling slightly. Instead, the last four years have been the hottest on record (UNWMO). 2016 was the warmest (an El Nino year) and we currently have El Nino conditions again https://youtu.be/Z4bSxb5THm4 Multiple studies published in peer-reviewed scientific journals show that 97 percent or more of actively publishing climate scientists agree climate-warming trends over the past century are extremely likely due to human activities. – climate.nasa.gov

The Industrial Revolution began in the late 1700’s . - marked a shift to powered machinery, factories and mass production (before that, we primarily used hand tools and simple machines)

Paleoclimatology - the study of changes in climate taken on the scale of the entire history of Earth. We know about past climates because of evidence left in tree rings, layers of ice in glaciers (ice cores), ocean sediments, pollen, fossils, coral reefs and layers of sedimentary rocks. https://youtu.be/O3T1a0CwCz4 https://www.youtube.com/watch?v=FLCgybStZ4g (permafrost – the tipping time bomb)

Why should we care about heating up a couple of degrees? Our local climate heats and cools many degrees every day, but that is not the temperature change that we are referring to. Earth’s GLOBAL temperature has heated. It takes A LOT of energy to heat all of the land, atmosphere and especially ocean (remember the specific heat of water?!). In the past, a 1-2 degree drop sent us into a little ice age and a 5 degree drop covered a large portion of North America with ice! https://youtu.be/R_pb1G2wIoA (Six Degrees Could Change the World) movie https://youtu.be/2_ZQRIsn2pA clip

Models predict that Earth will warm between 2 and 6 degrees Celsius in the next century. When global warming has happened at various times in the past two million years, it has taken the planet about 5,000 years to warm 5 degrees. The predicted rate of warming for the next century is at least 20 times faster. This rate of change is extremely unusual.

What else could account for this increase? Earth’s average temperature has generally increased from 1880. What else could account for this increase?

Remember that water has a high specific heat Remember that water has a high specific heat. It’s taken a long time to heat this much water and it will take a very long time for that heat to be lost, but the heat above the ocean will cause more evaporation. When the water evaporates, carbon is released into the atmosphere and warming increases.

Portage Glacier Heating causing glacier melt. Alaska 1914 2004

Colorado River Arizona June 2002 Dec 2003 This river should be getting bigger if melting creates more water, so what is happening? -increased evaporation -decreased precipitation -other locations are drying up and populations are increasing (increased damming and irrigation) Arizona June 2002 Dec 2003

Most carbon is held in “carbon sinks” which is a reservoir, such as an ocean or forest, that absorbs carbon dioxide from the atmosphere and stores the carbon in another form (H2CO3)

If these carbon sinks become saturated, they won’t be able to absorb more CO2 If permafrost melts, methane and CO2 released. If we chop down forests, they can not sequester (absorb and store) CO2. If increased temperatures cause ocean surface evaporation, CO2 is released into the atmosphere.

Burning of Fossil Fuels Pollution from coal, natural gas, and oil releases greenhouse gases into the atmosphere Pollution from coal, natural gas, and oil Pollution from coal, natural gas, and oil

Are feedback loops making the problem exponentially worse?

Why should we care?! Wildfire and storm destruction increase Loss of habitable area Drought and food loss Climate refugees Species loss at all trophic levels . . .and that’s only a few of the things that we can anticipate. . .

What’s being done now to reduce our emissions?

What’s being done now to reduce our emissions? Wind Power Solar Power Fuel-Efficiency

What can you do to help solve the problem? https://www.youtube.com/watch?v=VZVfNDcWOpU

Simple Things To Do REDUCE, REUSE AND RECYCLE Turn off your computer or the TV when you’re not using it. Take shorter showers. Heating water uses energy. Keep rooms cool by closing the blinds, shades, or curtains. Turn off the lights when you leave a room. Use compact fluorescent bulbs.

Be Bulb Smart—Use CFLs What’s the difference? Compact Fluorescent Incandescent 500 lbs. of coal 1,430 lbs. CO2 pollution avoided $30 saved

Simple Things To Do Dress lightly when it’s hot instead of turning up the air conditioning. Dress warmly when it’s cold instead of turning up the heat. Offer to help your parents keep the air filters on your AC and furnace clean. Walk short distances instead of asking for a ride in the car. Plant a tree.

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