A SelfGuided Tutorial The Wicked Problem of Global

A Self-Guided Tutorial The Wicked Problem of Global Food Security Introduction to the Climate System 1

Preparing for this Module After completing the activities in this slide stack, you will be able to: 1. Describe in general terms how unequal heating of the planet creates the patterns of air and ocean circulation, which in turn, are responsible for Earth’s latitudinal climate zones. 2. Create a diagram that shows how changes in the flux and residence time of carbon reservoirs are responsible for our warming climate. 3. Use an Earth system diagram to show changes in the Earth system challenges global food security. 2

Preparing for this Module This slide set introduces how climate zones are generated and discusses how increasing the flux of carbon into the atmosphere is responsible for changing climate. In this slide stack, there are four embedded short assignments where you will: • • Complete a reading assignment Write a paragraph summary to bring to class. Using these resources and the information in the slide stack, create a paragraph where you summarize your understanding of the Earth system, changing climate and potential or observed impacts on the global food system. You will bring this to class as your homework assignment. Expect to spend 1 hour on this homework activity Image: GLOBE. gov 3

The Earth System is ais. Climate System a Climate System Its all about Interconnections! • The Earth system behaves as a single, self-regulating closed system comprising physical, chemical, biological and human components. • The focus of Earth system science is understanding the interactions between water, air, life, geological processes and the land surface, and how those interactions impact each other and lead to changes on our planet. • These same ideas help us to understand how Earth’s climate is created. Image: GLOBE. gov 4

Unequal Heating Drives Air and Ocean Circulation Earth’s climate zones are the result of the Sun’s energy being unequally distributed on the planet’s surface. This is because as the angle at which the sunlight strikes the Earth surface increases, the amount of energy transmitted per area decreases: • • At 60 degrees latitude, energy per unit area is 50% of the intensity at the equator cooler warmer cooler Low density, high angle incident rays= less energy per square km High density, low angle incident rays= More energy per square km Low density, high angle incident rays= less energy per square km At 30 degrees latitude, energy per unit area is 87% of the intensity at the equator. The unequal heating of the Earth’s surface causes climate to vary by latitude. Image: Blue Marble from NASA Earth Observatory 5

Unequal Heating Drives Air and Ocean Circulation The unequal heating of the Earth’s surface causes climate to vary by latitude. Air and water circulation is initiated at the equator. Masses of air and ocean transport heat energy from areas of high concentration to low concentration. The movement of these masses of air and ocean establish an equilibrium state of heat distribution which we determine the general climate bands, or zones that we see at different latitudes. cooler ocean circulation warmer cooler Low density, high angle incident rays= less energy per square km atmospheric circulation High density, low angle incident rays= More energy per square km Low density, high angle incident rays= less energy per square km Image: Blue Marble from NASA Earth Observatory Unequal Heating Drives Air and Ocean Circulation 6

Unequal Heating Drives Air and Ocean Circulation Global Ocean and Atmospheric Circulation Determine Earth’s Climate Patterns A basic understanding of these circulation patterns will help you grasp the global, regional and local ramifications of the changes humans are making to our atmosphere and ocean. Polar Climates Moist mid-latitude climates: 30°-50° N and S of the equator Dry climates: 20°-35° N and S of the equator Tropical climates: 15° to 25° N and S of equator Dry climates: 20°-35° N and S of the equator Moist mid-latitude climates: 30°-50° N and S of the equator Polar Climates Map Image: NOAA Uneven heating of the Earth’s surface, combined with the transfer of energy by wind and ocean determines latitudinal climate zones 7

Unequal Heating Drives Air and Ocean Circulation Global Ocean and Atmospheric Circulation Determine Earth’s Climate Patterns Assignment This video summarizes how ocean and atmosphere serve to redistribute heat on the planet’s surface. http: //svs. gsfc. nasa. gov/cgi-bin/details. cgi? aid=11056 8

Describing Climate. The Köppen climate classification is based on the idea that vegetation associations seen on the landscape are the expression of the climate in which they evolved. Climate classification maps created using the Köppen climate classification system display boundaries that are based on vegetation distribution, which in turn provides a “proxy” indication of seasonal temperatures and precipitation. Today the classification also employs quantitative climatological data in assigning boundaries between units. Describing climate using the Köppen Climate Classification System 9

Describing Climate. Activity: To learn more about the classification scheme we will be using in the map activity, go to the website linked below and look at the designations around the world. For instance, for its designator B, the Sahara desert in North Africa has dry arid and semiarid climates, characterized by actual precipitation less than a specified threshold value set equal to the potential evapotranspiration. If you do not understand some of the terms (e. g. , potential evapotranspiration), do not worry. You can certainly do some exploration on your own. Since the annual precipitation of this area is less than 50% of this threshold, it is BW (desert climate). The third letter “h” indicates that the coldest month has an average temperature above freezing. Find your location on the map. What is the letter designation of your area of interest, and what does it describe, in climate terms? Pidwirny, M. (2011). Köppen Climate Classification System. http: //www. eoearth. org/view/article/162263 Describing Climate using the Köppen Climate Cassification System 10

Describing Climate. To learn more about the classification scheme, go to the website link below and look at the designations around the world. For instance, for its designator B, the Sahara desert in North Africa has dry arid and semiarid climates, characterized by actual precipitation less than a specified threshold value set equal to the potential evapotranspiration. Since the annual precipitation of this area is less than 50% of this threshold, it is BW (desert climate). The third letter “h” indicates that the coldest month has an average temperature above freezing. You don’t need to remember the specifics of the naming system, just remember that the Köppen Classification System is used to describe climate in different regions, because you will encounter it later in the mapping activity. 11

II. Climate Change You’ve just explored the basic physical science behind the positions of Earth’s climate zones. Within these zones there is significant variation that result from the influences of topography and proximity to water bodies and ice, soil and substrate, and vegetation. These factors contribute to the complex system of biomes we have on the Earth’s surface. Also, weather conditions vary from year to year because of ocean and atmospheric conditions, resulting in extreme events such as droughts, floods, hurricanes and typhoons. In some regions, events such as these are periodic and quasi-periodic and cultures have developed important redundancies in their production systems and storage strategies to ensure the availability of food in times when production conditions are suboptimal. A stable and predictable climate has enabled agriculturists to provide reliable harvests and a constant food supply for their communities. Thousands of years of human innovation has resulted in crop varieties, food animals and agricultural practices and decision making that are finely adapted to each of the unique environmental conditions where traditional agriculture has taken place. But what if those stable and predictable climate conditions disappear? What do you think the consequences of a warming climate will be on the global food production system? How will these changes impact the other parts of the global food system? The next section of this slide set is a short presentation about climate change. This is in preparation for a climate and biome mapping activity that will be conducted next class. 12

II. Climate Change A 30 Second Lesson on Climate Change Amount and rate of energy entering the Earth system = energy exiting, no change Amount and rate of energy entering the Earth system =/= energy exiting, change occurs • The amount of radiation from the Sun on human time scales does not change (solar constant), so the only thing that can cause warming is changing the rate at which energy leaves the Earth system. • When the rate of heat energy leaving the system is hindered by molecules in the air that absorb energy and reflect it back to Earth instead of releasing it to space, heat builds up and increases the temperature of the system. • By adding greenhouse gases into the atmosphere, we increase the amount of gases in the air that absorb energy, so energy is not released to space as fast as it accumulates. • The rate of heat accumulation is increased because (1) we are moving carbon out of fossil fuel reservoirs, combusting it, and releasing into the atmosphere as CO 2, and (2) once greenhouse gases (like CO 2) are increased in the atmosphere, these molecules persist for decades and serve to retain the heat energy in the system. • This is the mechanism by which our climate warms. A 1 Minute Lesson on Climate Change 13

II. Climate Change When the rate of heat energy leaving the system is hindered by molecules in the air that absorb energy and reflect it back to Earth instead of releasing it to space, heat builds up and increases the temperature of the system. You may remember that the Earth is a closed system with respect to matter, but is an open system with respect to energy. About 29% of incoming sunlight is reflected back to space by bright particles in the atmosphere or bright ground surfaces, which leaves about 71%t to be absorbed by the atmosphere (23%) and the land (48%). For the energy budget at Earth’s surface to balance, processes on the ground must get rid of the 48% of incoming solar energy that the ocean and land surfaces absorb. (Source: NASA Earth Observatory). If we do not lose energy at the rate in which we obtain it, the system warms. The Earth System is our Climate System 14

II. Climate Change • The amount of radiation from the Sun on human time scales does not change (solar constant), so the only thing that can cause warming is changing the rate at which energy leaves the Earth system. Changes in the Sun’s luminosity has an effect on Earth’s climate on the scale of tens of millions of years, but do not account for the recent warming of our planet. Earth’s eccentric orbit around the Sun and changes in the tilt of Earth’s axis with respect to the Sun affect climate on geological time scales of 10, 000 to 100, 000 years, and cannot account for the recent warming of our planet. It is not an increase in the of amount of energy coming in, but the rate of energy transfer of solar energy out. Images: NASA Earth Observatory/ 15

II. Climate Change • By adding greenhouse gases into the atmosphere, we increase the amount of gases in the air that absorb energy, so energy is not released to space as fast as it accumulates. • The rate of heat accumulation is increased because (1) we are moving carbon out of fossil fuel reservoirs, combusting it, and releasing into the atmosphere as CO 2, and (2) once greenhouse gases (like CO 2) are increased in the atmosphere, these molecules persist for decades and serve to retain the heat energy in the system. Review Terminology: Reservoir: the volume or mass of matter or of energy stored in a system Residence Time: the average amount of time that matter remains in a reservoir Flux: describes the movement of mass and/or energy between reservoirs Image: NASA GLOBE In your notes: Identify the fluxes and reservoirs in the carbon cycle that are contributing to our warming climate. Changing Where Our Carbon is in the Earth System 16

II. Climate Change Fast and Slow Carbon Watch this short video that describes the idea of residence time by discussing “fast carbon and slow carbon”. You will see that this video is talking about fluxes between carbon found in reservoirs in the lithosphere and biosphere. By fast carbon, the video is referring to carbon’s short residence time (in a banana) and long residence time (in coal). By moving carbon in fossil fuels out of storage and into the atmosphere, we are adding carbon to the atmosphere much faster than it can be removed by Earth system processes. Review: Dissolved CO 2 in the Ocean has a residence time of about 500 years in the reservoir in the hydrosphere. The residence time of carbon in life forms is variable, depending on their life span, and how rapid they decay: reservoir of the biosphere. Coal, petroleum and natural gas have a residence time of millions of years in the lithosphere, however this is reduced through use of fossil fuels. Climate Bits: Fast Carbon, Slow Carbon Credit: http: //climatebits. umd. edu/ CO 2 has a residence time of hundreds of years in the reservoir of the atmosphere. 17

II. Climate Change Climate is changing. How can we prepare for the future? How can we ensure that our agricultural production systems are responsive to the future changes and are able to provide sufficient food to people around the globe? We can’t predict the future, but by understanding the processes that take place within the Earth system, and by describing the interactions between air, water, life, and land quantitatively, we are able to develop accurate projections of future conditions that can be used in planning for food production on a warmer Earth. How Can We Prepare for a Warming World? 18

II. Climate Change Climate Models Allow us to Project Future Climate Changes …and allow us to begin to prepare for a warmer world. A quantitative understanding of the processes and fluxes in the Earth system is critical to our ability to understand the changes that are occurring in our climate. The climate system is both affected by and in turn impacts the overall system in direct and complex ways and it operates at local regional and global scales. A quick glance at this diagram shows the complexity of the Climate System – and the many interactions and processes at work. This is why supercomputers are needed to run climate models! In the mapping activity, you will be using the output from Global Climate Models (GCMs) to project future changes in climate, and consider how these changes will impact the global food system. Image: USGCRP 19

II. Climate Change Reading Assignment You have already read an except of Steve Easterbrook’s blog post. Now read the entire post, paying attention to his discussion of Why Systems Thinking, as he refers to how we build understanding of the climate system. There additional links to other excellent resources that delve deeper into greenhouse gases and Earth system feedbacks if you are interested. http: //www. easterbrook. ca/steve/2013/08/why-systems-thinking/ 20

II. Climate Change Writing Assignment (one paragraph) Suggest one way that a changing climate could impact the global food system: food production, food distribution, or food quality. You can use the diagram on the left as an example. Create a diagram showing appropriate feedbacks/ fluxes linking 3 or more spheres. Bring your paragraph and diagram to class. Crop failure More frequent droughts And floods Warmer atmosphere Climate warming Enhanced water cycle CO 2 release from lithosphere 21

II. Climate Change Make a Note Before you complete this activity, make notes about any questions that you have that can be discussed by the group Thanks for completing this tutorial. It will allow us to have richer conversations in our face-to-face meeting. “We cannot solve our problems with the same thinking we used when we created them. ” – Albert Einstein 22

II. Climate Change Moving Forward As you learn more about Earth’s climate and global change, or even as you simply think about what is happening in the natural world around you, keep in mind the concept of the Earth system, with its spheres, reservoirs of matter and energy, and processes that drive matter and energy fluxes from one sphere to another. These concepts can help you better understand the very dynamic nature of our planet, even when processes happen at rates that are much more gradual than the eruption of a volcano or flooding that results from a wild storm. The global food system is inextricably linked and responsive to the Earth system, and a warming climate is a factor that needs to be addressed in any effort to address global food security. 23

II. Climate Change Revised and expanded version developed for inclusion in module, “Addressing the Wicked Problem of Global Food Security, ” (September 2015) Russanne Low Original Artwork: Jenn Glaser and Russanne Low, Scribe. Arts for the GLOBE Program 24