What is Climate Change and Why Is It Happening?

An article directed toward homeschool/unschoolers as a basic primer for climate change. Presented in question and answer format.  

What is climate change? 

The IPCC is the Intergovernmental Panel on Climate Change and is part of the Untied Nations. According to the IPCC, climate change is “a change in the state of the climate that can be identified by changes in the mean [average temperature] that persists for an extended period, typically decades or longer (Climate, 2007)” 

How can the Earth’s temperature change?

There are only three ways for the temperature of the Earth to change: 

  • If the amount of energy the Earth receives from the Sun changes

  • If the amount of energy that the Earth radiates back out into space changes

  • If the thickness of Earth’s atmosphere changes (Calculating, n.d.)

How does the Sun impact the climate? 

The Sun emits electromagnetic energy to the Earth. The energy received by the Earth from the Sun must be balanced by energy the Earth emits back out to space (Earth, n.d.)

Why is the Earth warm at all? 

Mathematic models predict that the Earth should be -0.67°F. Thermometers show Earth actually has an average temp of 59°F (Predicted, n.d.)

What explains the difference between the model’s predicted and the Earth’s actually measured temperature? 

The atmosphere! The atmosphere works like a blanket thrown over the Earth (Atmosphere, n.d.) 

What is the greenhouse effect?

When energy from the Sun passes through the Earth’s atmosphere to the surface, the Sun’s energy is converted to heat and radiated back out to space. Some of the heat energy radiated from the Earth becomes trapped by greenhouse gases in the atmosphere (A Greenhouse, n.d.)

Greenhouse gases include what?: 

  • Water Vapor

  • Carbon Dioxide (CO2)

  • Methane 

  • Nitrous oxide 

  • Fluorinated gases (Global, n.d.)

Why is CO2 important? 

CO2 lasts in the atmosphere for thousands of years (Understanding, n.d.) and CO2’s atmospheric concentration is rapidly increasing (Harvey, 2017) 

What are atmospheric CO2 concentrations? 

CO2’s concentration in the atmosphere can be expressed as Parts Per Million (PPM) 

  • In 1750, CO2 measured 275 PPM 

  • In 1960, CO2 measured 315 PPM 

  • In 2020, CO2 measured 414 PPM (Latest, 2020)

Why is CO2 increasing? 

CO2 is a by product of human industrialization 

What are the main sources of anthropogenic (human released) CO2? 

  • Transportation - 28.5%

  • Electricity - 28.4%

  • Industry - 22% 

  • Heating homes and businesses - 11%

  • Agriculture - 9%

  • Other - 1.1%

What is climate sensitivity? 

Climate sensitivity is amount that the temperature will increase if the concentration of CO2 in the atmosphere is doubled from the pre-industrial era

Why is climate sensitivity important? 

Climate sensitivity is a rough estimate of how much greenhouse gases will increase the temperature of the Earth. The IPCC predicts that a doubling of CO2 from the pre-industrial era will create a temperature increase of 2 to 4.5 degrees celsius (Chandler, 2010). Humans add 40 billion tons of CO2 to the atmosphere annually (Plait, 2014). Since 1900, global temperatures have increased by close to 1 degree C (Climate Change, n.d.)

What is human caused climate changed called? 

Anthropogenic climate change. The word combines “anthro,” which means human, and “genic,” which means produced by

Why is climate change important? 

Throughout history, many human societies have been wiped out by climate change: 

  • Ancestral Pueblos in the US southwest 

  • Indus Valley civilization of present day Pakistan

  • Norse Viking settlers of Greenland

  • Khmer Empire of ancient Cambodia

  • Mayan Empire in Central America (Leary, 2016)

  • Akkadian in Mesopotamia (Drought, n.d.)

  • Mississippian culture in the US mid-west and southeast (Chen, 2017)

How can human’s impact on the climate be determined? 

Look at the Keeling Curve record of atmospheric CO2 concentrations of the last 60 years (Latest, 2020): 

mlo_full_record.png

Compare the Keeling Curve to NASA’s temperature record from 1880 to present: 

Screen Shot 2020-02-06 at 1.56.11 PM.jpg

From 1960 to present, notice the strong linear trend (correlation) between the CO2 concentration in the Keeling Curve and measured temperature increases (GISS, 2020)

References can be found here