Intro. to the Greenhouse Effect Climate and Climate Change

Intro. to Greenhouse Effect: Outline Atmospheric Gases: “Greenhouse” or Not? – How gases can store heat energy Step-by-Step of the Greenhouse Effect – How energy enters Earth’s systems – How energy is absorbed and retained Impact on Earth’s Climate – Prehistoric data – Modern data

Atmospheric Gases: Non-“Greenhouse” These gases are simple, either one atom or two. They store energy through translating or (sometimes) rotating.

Atmospheric Gases: “Greenhouse” These gases are complex, at least three atoms bonded together. They store energy through translating, rotating, or complex vibrations. For extreme physics details, CLICK HERE

Greenhouse Effect Steps: Overview

Greenhouse Effect Steps: 1. Sun’s Energy Enters Most of the atmosphere is transparent to “visible” light – Why you can see through it most of the time Most incoming solar radiation is “visible” kind (see graph later) By Handyhuy (Own work) [CC-BY-SA-3.0 ( via Wikimedia Commons

Greenhouse Effect Steps: 2. Ground Absorbs Energy You can’t see through the Earth’s surface – Ground and other surface features absorb visible light and heat up E.g., dark objects absorb more light and heat up more easily

Greenhouse Effect Steps: 3. Ground Radiates IR Energy Infrared radiation (IR) is released from warm bodies – E.g., the hot ground releases it in all directions “Night vision” goggles pick up IR, by the way By Brocken Inaglory (Own work) [Public domain], via Wikimedia Commons

Greenhouse Effect Steps: 4. GHGs Absorb IR Energy Greenhouse gases (GHGs) have the complex motions that match the IR energy – IR traveling from the surface hits gases – GHGs begin vibrating (i.e., heating up, storing the energy) Heated GHGs also release IR! By Nick84 [CC-BY-SA-3.0 ( via Wikimedia Commons

Greenhouse Effect Steps: Revisited

Impact on Earth’s Climate: Prehistoric Data By Vostok-ice-core-petit.png: NOAA derivative work: Autopilot (Vostok-ice-core-petit.png) [CC- BY-SA-3.0 ( or GFDL ( via Wikimedia Commons

Impact on Earth’s Climate: Modern Data (Slide 1) By US Govt (NOAA ( [Public domain], via Wikimedia Commons

Impact on Earth’s Climate: Modern Data (Slide 2) “Global mean land-ocean temperature change from 1880–2013, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean. The green bars show uncertainty estimates.” By NASA Goddard Institute for Space Studies ( [Public domain], via Wikimedia Commons Wikipedia contributors. "Global warming." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 12 Oct Web. 14 Oct

Check yourself Is heat trapped on the way in or the way out? Given what you know about Mars and/or Venus, how do you think the greenhouse effect impacts their climates? How “effective” a greenhouse gas do you think the following molecule is? By Walkerma (Own work) [CC0], via Wikimedia Commons