ESC 211 Unit 2

define source

Sources refers to either natural sources or human activities (anthropogenic) that release these gases into the atmosphere

explain the keeling curve

This graph (Keeling Curve) shows CO2 concentrations in the atmosphere measured at an observatory in Hawaii (northern hemisphere). The trend is increasing, but each year the amount fluctuates up/down as vegetation grows in summer (uptakes CO2) and dies off in winter

__________ says more about what we are experiencing in any particular location; while __________ addresses the average temperature rise for the Earth as a whole

*climate change* says more about what we are experiencing in any particular location; while *global warming* addresses the average temperature rise for the Earth as a whole

explain carbon pools/sinks

- Carbon is stored on our planet in pools. - "Pools" is a term used to refer to storage places. These are also called "sinks". - When carbon is released, the pools/sinks turn into "sources"

Summary: Global warming/climate change theory

- Climate change will result from global warming ---Global average temperature is increasing. ---Climate is changing on global, regional and local scales. - Global warming refers to the increase in global temperature --- that is, for the average temperature for the planet as a whole over a period of time - Warming of the earth's global average temperature results from increases in greenhouse gases. --- As we increase our contributions to the amount of greenhouse gases in the atmosphere, global temperature should be increasing (and it is!). --- This leads to changes in climate on global, regional and local scales

explain the carbon cycle with and without humans

- In 1750, WITHOUT industry & vehicles, there was around 288 CO2 molecules in every million air molecules - In January 2020, WITH industry & vehicles, there is now 413 CO2 molecules in every million air molecules (69% increase)

explain how a new equilibrium IN = Out will be reached, with a higher global temperature

- Once greenhouse gas emissions into the atmosphere are stabilized, the global energy balance will also stabilize and be maintained. - But there will be a "lag time" between when we no longer keep increasing our inputs of gases and when global temperature stops rising. - In other words, global warming will continue for some time beyond stabilization of gas concentrations. How long? Different models predict anything form 100 -1000 years

explain surface (tropospheric) ozone (O3)

- Ozone that is found near the surface is a human-caused pollutant. This is NOT the same as the natural stratospheric ozone layer (that is the layer that protects us from harmful ultraviolet light). - Sources of anthropogenic surface ozone: fossil fuel combustion byproducts that interact with gases in sunlight. - Surface ozone is a very "transient gas", that is, highly unstable. This means it breaks down very quickly into oxygen. This chemical process is its only sink.

explain the sources and sinks of methane

- Sources: >>Natural sources: wetlands, termites >>Anthropogenic sources: ruminants (e.g. cows), coal- mines, natural gas and oil wells - Sinks: soil is known to absorb small amounts of methane. - Methane is a very powerful greenhouse gas. It absorbs more infrared than CO2 per unit, but since there is not near as much methane in the atmosphere, it plays a much smaller role in enhancing the greenhouse effect. - Pre-industrial levels: 700 ppb (parts per billion) - Today: 1,745 ppb

nitrous oxides sources and sinks

- Sources: >>Natural: Occasional volcanic eruption. >>Anthropogenic: burning organic material, fossil fuel burning, fertilizers, bare soils - Sinks: Reactions in sunlight convert this gas into other noxious pollutants. - Pre-industrial levels: 270 ppb - Today: 314 ppb

what are the four most important feedbacks

- There are many climate feedbacks, but the following are four important feedbacks when considering climate change: Water vapor feedback, Ice/snow albedo feedback, Cloud feedback, Vegetation feedback - For the most part, these operate as positive feedbacks (even when they have a cooling effect)

explain halogenated gases

- These gases are entirely anthropogenic. There are no natural sources of CFCs, HCFCs and PerCFCs (PCFCs). >> coolants in refrigerators and air conditioners >> propellants in spray cans and industrial solvents. - For all of these combined: >> Pre-industrial level: 0 >> Today: highly variable, ranging from 60-500+ppb - Most CFCs have been banned worldwide. They are very toxic. *(CFCs= Chlorofluorocarbons HCFCs = hydrogenCFCs)*

an increase in average global temperature leads to

- an enhanced greenhouse effect, that leads to anthropogenic climate change - It leads to changes in climate patterns throughout the world, all depending on location: More/less rainfall More/less snowfall Stormier/less stormier Hotter/cooler temperatures - Also leads to changes in patterns of ocean currents, ice melt/freeze, sea level

If the quantity of greenhouse gases increases in the atmosphere, theoretically this should lead to:

- an increase in the retention of outgoing terrestrial thermal radiation - an imbalance in the IN = OUT equations for a time, with less radiation exiting than entering ---This imbalance will occur ONLY while gas concentrations are increasing ---Eventually a new equilibrium will be reached (explained more on next slide) - a gradual increase in the earth's average global temperature

Global warming refers to the fact...

- that Earth's global temperatures are rising; however, this does not equate to warming in all regions - that the climate is warming, but also that the warming can manifest itself differently across the earth, leading to extreme weather events, melting ice sheets, and even cooler ocean temperatures in some areas

which carbon pools have the most about of carbon

As you can see, marine (ocean) sediments and rocks store a huge amount of carbon. Most of this is tied up in the rocks, and not likely to be released (or at least, not easily released)

explain how carbon is accumulated in the carbon cycle

Carbon (as CO2) is accumulated (stored)... - Photosynthesis uses sunlight to make carbohydrate from CO2. - Carbon is deposited in deep ocean sediments - Organic carbon dissolves in ocean water - Carbon is stored in soils

explain how carbon is released in the carbon cycle

Carbon (as CO2) is released... - Respiration - carbon is oxidized for energy. - Combustion - carbon is burned - Weathering and erosion - rain (slightly acidic) weathers calcium carbonate rocks and soils erode - Diffusion of carbon from ocean water surface into the atmosphere

anthropogenic greenhouse gases include...

Carbon Dioxide Methane Nitrous Oxides Surface Ozone (this NOT stratospheric ozone that protects us from harmful Ultraviolet radiation!) Chlorofluorocarbons (CFCs) and HydroCFCs Sulfur Hexafluoride - Many of these are also found naturally, but we are increasing the amount of these gases in the atmosphere - Others are NOT natural at all, and are entirely anthropogenic: Halogenated gases (CFCs, HCFCs) and Sulfur hexafluoride

what is carbon

Carbon is an element fundamental to the natural greenhouse effect as well as the enhanced effect (global warming). It combines with other elements to produce greenhouse gases, such as carbon dioxide (CO2) and methane (CH4)

define feedbacks

Feedback - Occurs when the flow of energy or matter in one pathway acts to either reduce or to increase the flow in another pathway. - With respect to climate: >> Positive feedback - Where the feedback reinforces, or increases, an initial trend. >> Negative feedback - Where the feedback reduces, or decreases, an initial trend.

define sinks

Sinks is a term used to refer to a location, process or environment that removes the gases from the atmosphere

explain sources and sinks of carbon dioxide

Sources: >> Natural: ancient long-term development due to biomass, occasional volcanic eruption today. >> Anthropogenic: fossil fuel burning, burning of biomass (grasses, forests) - Sinks: >> Vegetation - forests and grasslands are major sinks >> Ocean - dissolving in the water or by plankton - Pre-industrial levels: 288 ppm - Today (January 2020): 413 ppm

define the carbon cycle

The carbon cycle is the movement of carbon through the environment, between the atmosphere, surface, underground, and life. We must also include in the cycle human-made systems, such as transportation

explain ocean carbon pools

The carbon stored in the ocean is primarily dissolved

The gases we emit into the atmosphere (and also the natural ones as well) all have...

The gases we emit into the atmosphere (and also the natural ones as well) all have "sources" and "sinks." - Sources, as the word implies, are where the gas comes from. - Sinks refers to anything or method that removes the gases from the atmosphere

where are the different carbon pools located

atmosphere, terrestrial plants, soil organic matter, ocean, fossil fuel deposits, marine sediments and sedimentary rocks

define Global Warming Potential (GWP)

refers to the potential warming impact a gas has. It is measured relative to CO2. It depends on a gas's efficiency (radiative forcing ability) and lifetime (how long it stays in the atmosphere)