(Relocation to Auditorium) Wednesday May 9, 2018 (Discussion – Human Impact on Global Climate; Energy Consumption; The Atmospheric Response) (Relocation to Auditorium)

The Launch Pad Wednesday, 5/9/18 1/1 No Launch Pad Today!

Announcements Earth/Space classes will meet in the Auditorium again tomorrow! Please check in with me and sit in a group!

Remediation for Quiz 17 begins todays and runs through next Wednesday! Announcements Remediation for Quiz 17 begins todays and runs through next Wednesday!

Summative or Formative # eResearch Paper - Climate Assignment Summative or Formative # Date Issued Gone Missing Day Last Day Accepted eResearch Paper - Climate F2 5/7 Next Tuesday QUIZ 17 S2 5/8 Next Wednesday

Climate Change

Human Impact on Global Climate Humans have been modifying the Earth’s environment over extensive areas for thousands of years. The use of fire changes the environment. Overgrazing of marginal lands can cause changes as well. Most hypotheses of climatic change are to some degree controversial due to lack of understanding or refusal to acknowledge.

Global Warming Water vapor and carbon dioxide absorb heat and are largely responsible for the “greenhouse effect” of the atmosphere. Burning fossil fuels has added great quantities of carbon dioxide to the atmosphere.

Is this a good thing or a bad thing? The Greenhouse Effect The greenhouse gases carbon dioxide, water, methane, ozone, and nitrogen oxides trap solar radiation in the Earth’s atmosphere. Is this a good thing or a bad thing? Trapping of the right amount of solar radiation by greenhouse gases keep the Earth’s temperature relatively constant, allows water to exist in the liquid state, and makes Earth “livable.” Trapping of too much greenhouse gas contributes to global warming and is threatening to make the Earth harder to live on.

Figure 20.17

CO2 concentrations over the past 1 000 years Fossil fuel CO2 emissions

Americans are responsible for about 25% of the world’s greenhouse gas emissions.

The Atmospheric Response It is a fact that global temperatures have increased. The balance of evidence suggests a human influence on global climate change. Our globally-averaged surface temperature is projected to increase by 34 to 42ºF by the year 2100. Average global temperature variations 1860–2006

The Atmospheric Response Atmospheric trace gases like methane, nitrous oxide, and certain chlorofluorocarbons, absorb wavelengths of outgoing Earth radiation. Taken together, their warming effects may be nearly as great as carbon dioxide.

The left half of the graph shows global temperature changes for the 20th Century. The right half shows projected global warming in different emissions scenarios. The shaded zone adjacent to each colored line shows the uncertainty range for each scenario. The basis for comparison (0.0 on the vertical axis) is the global average for the period 1980-1999. The orange line represents the scenario in which CO2 concentrations were held constant at the values for the year 2000.

Climate-Feedback Mechanisms Climate is a very complex interactive physical system. Thus, when any component of the climate system is altered, scientists must consider many possible outcomes. These possible outcomes are called climate feedback mechanisms.

Use today’s notes on the website (5/9) Worksheet Use today’s notes on the website (5/9) Human Impact on Global Climate; Energy Consumption; The Atmospheric Response