ENVS 202 1st Edition Lecture 10Outline of Last Lecture MidtermOutline of Current Lecture I. Climate ChangeII. The AtmosphereIII. Greenhouse GasesCurrent LectureI. Climate ChangeHow do we disentangle natural processes with those that are indicative of climate change?What are some indicators of climate change?Glaciers, global average temperature, changing migration patterns, CO2 levels, sea level riseGoing up: ocean heat content, sea level, sea surface temperature, temperature over oceans,water vapor, air temperature near surface, temperature over landGoing down: sea ice, glaciers and ice sheets, snow coverII. The AtmosphereWhat gases make up the atmosphere?Oxygen, nitrogen, carbon dioxide, methaneWhich are most abundant? Nitrogen, oxygen, water, argonWhich are increasing due to anthropogenic causes?Carbon dioxide, methane, ozone, carbon monoxide, nitrous oxideThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.The atmosphere is layeredTroposphere, stratosphere, mesosphere, thermosphereTemperature cools as you go up until you reach the stratosphere, where ozone traps UV and causes warmingPressure decreases exponentially as you go upWhat are the possible paths of solar energy hitting Earth?Reflected by clouds, absorbed by clouds, Earth absorbs ~45%, Earth reflects someHow much is radiated back into space?Infrared radiation emits from Earth’s surface, it is either reradiated as longwave infrared radiation, or kept in the atmosphere by greenhouse gasesWhat influences how heat is radiated?The sun is much hotter than Earth, so it emits radiation at shorter wavelengths (on the visible spectrum)Do the poles emit as much energy as they absorb?Much more is absorbed at the equator than the polesThe poles emit about the same radiation as the equatorSurplus of equatorial heat, deficit of polar heatWeather redistributes heat and energy to the poles to keep up a steadt-state balanceOcean circulation transfers heat (40%), atmosphere transfers sensible heat (30%), atmosphere transfers latent heat (30%)III. Greenhouse GasesWhat else influences Earth’s heat balance?Greenhouse gases absorb longwave radiation and reradiate it, which warms the Earth’s surfaceWhat are the major greenhouse gases?Water vapor, carbon dioxide, methane, nitrous oxide, ozoneWhat are some anthropogenic sources of these gases?Carbon dioxide: combustion of organic matter, fossil fuels, cement manufacturingMethane: anaerobic decay (wetlands), agriculture, ruminants, wastewater treatment, leaky transmission linesNitrous oxide: fertilizer, animal wastes, fossil fuel combustionWhat is the percentage of CO2 in the atmosphere today? 0.04%This is a big deal because it is continuing to rise, it correlates with the rise in