Greenhouse Gases, Feedbacks, and Scenarios

What is the relationship between increasing amounts of greenhouse gases and global climate change?  As the NASA article stated, most climate scientists agree the main cause of the current global warming trend is human expansion of the greenhouse effect, warming that result when the atmosphere traps heat radiating from Earth toward space.  Long-lived gases such as aerosols remaining semi-permanently in the atmosphere which do not respond physically or chemically to changes in temperature are described as "forcing" climate change, whereas gases such as water which respond physically or chemically to changes in temperature are seen as "feedbacks."  Gases that contribute to the greenhouse effect include:  Water vapor, Carbon dioxide, Methane, Nitrous oxide, and synthetic compounds of Chlorofluorocarbons.

On Earth, human activities are changing the natural greenhouse.  Over the last century the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO₂).  This happens because the coal or oil burning process combines carbon with oxygen in the air to make CO₂.  To a lesser extent, the clearing of land for agriculture, industry, and other human activities have increased concentrations of greenhouse gases.

Certain effects seem likely:

• On average, Earth will become warmer.  Some regions may welcome warmer temperatures, but others may not.
• Warmer conditions will probably lead to more evaporation and precipitation overall, but individual regions will vary, some becoming wetter and others dryer.
• A stronger greenhouse effect will warm the oceans and partially melt glaciers and other ice, increasing sea level.  Ocean water also will expand if it warms, contributing further to sea level rise.
• Meanwhile, some crops and other plants may respond favorably to increased atmospheric CO₂, growing more vigorously and using water more efficiently.  At the same time, higher temperatures and shifting climate patterns may change the areas where crops grow best and affect the makeup of natural plant communities.

Aerosols are forcings that can influence climate by scattering light and changing Earth’s reflectivity, they can also alter the climate via clouds.  On a global scale, these aerosol “indirect effects” typically work in opposition to greenhouse gases and cause cooling.  While greenhouse gases disperse widely and have a fairly consistent impact from region to region, aerosol effects are less consistent, partly because of how the particles affect clouds.  In fact, most clouds owe their existence to aerosols that serve as the tiny “seeds,” called cloud condensation nuclei.

Natural aerosols—often sulfates, sea salt, or ammonium salts—are the most common condensation nuclei in pristine environments.  Polluted air, in contrast, usually contains much higher concentrations of water-soluble particles, which means pollution-rich clouds tend to have more numerous, but smaller droplets.  The small droplets make polluted clouds look brighter than they would otherwise.  Just as many bits of crushed ice give light more surfaces to reflect off of, appearing brighter than a solid cube of ice, if the water in a cloud is divided into a larger number of smaller droplets, it will scatter more light and become more reflective.  Despite their small size, they have major impacts on our climate and our health.  http://earthobservatory.nasa.gov/Features/Aerosols/page1.php

In its recently released Fourth Assessment Report, the Intergovernmental Panel on Climate Change, a group of 1,300 independent scientific experts from countries all over the world under the auspices of the United Nations, concluded there's a more than 90 percent probability that human activities over the past 250 years have warmed our planet.  The industrial activities that our modern civilization depends upon have raised atmospheric carbon dioxide levels from 280 parts per million to 379 parts per million in the last 150 years.  The panel also concluded there's a better than 90 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in Earth's temperatures over the past 50 years.  (Global Climate Change-National Aeronautics and Space Administration) http://climate.nasa.gov/causes/

So, the Woods Hole Research Center said that greenhouse gases act like an insulator or blanket above the earth, keeping the heat in.  Increasing the concentration of these gases in the atmosphere increases the thickness of this insulator, therefore increasing the atmosphere's ability to block the escape of infrared radiation.  Too great a concentration of greenhouse gases can have dramatic effects on climate and significant repercussions for Earth.  Too low a concentration can have dramatic effects as well.  http://www.whrc.org/resources/primer_greenhouse.html

Imperfect understanding of climate feedbacks is a major cause of uncertainty and concern about global warming.  How can the use of climate models help in the understanding of these uncertainties?  Uncertainty is due to the lack of complete knowledge of how the climate works, which will lessen with further study.  Other uncertainty is due to natural variability in the climate system, which will not go away.  And an additional element of uncertainty is due to the inability to predict human behavior and its cumulative impact on the earth’s climate.  The Center on Research for Environmental Decisions stated that Global climate models are used to predict what will happen to Earth’s climate in the future and to help in the understanding of these uncertainties.  Groups like the Intergovernmental Panel on Climate Change (the IPCC) compare the results from several different climate models as they figure out what is most likely to happen.  http://www.cred.columbia.edu/guide/guide/sec5.html

To figure out whether a climate model is doing a good job, scientists give it a test.  The model is run through a time period for which actual measurements of Earth’s climate are gathered, for example the past 100 years.  The results from the model are compared with the actual measurements of real climate.  If the model and the actual measurements are similar, then the math equations in the model that are used to describe how Earth works are probably quite accurate.  If the model results are very different from our records of what actually happened, then the model needs some work. 

Some of the uncertainty about our future climate is because there are processes and feedbacks between different parts of the Earth that are not fully understood.  These are difficult to include in the models until they are better understood.  Today, scientists are conducting research to learn more about how some of the less well-known processes and feedbacks work.  For example, as the Windows to the Universe website stated, the effects of clouds on climate is known to be a large, however it is not fully understood and so scientists are researching clouds to ensure that climate models are as accurate as possible.  Scientists work to ensure that natural processes are represented in climate models as accurately as possible in order for them to be used to make predictions of future climate that are as accurate as possible.

Most of the uncertainty in these predictions of future climate is not related to natural processes.  Instead, it is uncertain how much pollution humans will be adding to the atmosphere in the future.  Innovations that stop or limit the amount of greenhouses gases that are produced, laws and rules that change the amount of pollutants that are released, and how the growing human population lives in the future are all somewhat unknown.  To deal with this, climate models are often run several times, each time with different amounts of pollution and development

http://www.windows2universe.org/earth/climate/cli_models4.html

With regards to the six emission scenarios, what is the evidence existing today that would suggest that one or more of the scenarios may occur within the next 100 years?  There may be evidence existing today that may suggest that the A1T scenario may occur within the next 100 years.  There are different projects toward restoring and conserving the earth by going green and using natural energy sources, such as solar power.  Also, there is a continuous growth in technology now.  I believe that will continue.  Gas prices continue to increase.  As gas prices increase in the US and abroad there will be a shift toward renewable energy sources.  This is already becoming an issue as we see more and more consumers opting for energy efficient cars and hybrids.  Another more recent technology has been the conversion of hydrocarbons or coal to basic fuel that can then be refined into gasoline, kerosene, and other fuels needed.  Some politicians have spoke about nuclear energy as an alternative to coal and there are subsidies currently in place for growing wind and solar technologies.  Wind projects and solar projects have been on the rise.  However, this scenario is highly unlikely because big businesses are too greedy for us to actually go completely with non-fossil fuel energy sources within the next 100 years.  Their mindset is not there as of yet.  http://www.darvill.clara.net/altenerg/

Nevertheless, of the six scenarios A1F1, A1B, A1T, A2, B1, B2 developed by the Intergovernmental Panel on Climate Change (IPCC), the most probable ones that will occur in the next one hundred years is A1B and B1.  A1B scenario’s emphasis is a balance on all resources.  Its driving forces are a rapid economic growth, a rapid growth and then decline in population, and a rapid spread of new and efficient technologies.   B1 scenario’s emphasis is on global solutions to economic, social, and environmental stability.  Its driving forces are a rapid economic growth as in A1B, but with rapid changes towards a service and information economy, a continuous increase of the population, and a reduction in material intensity and the introduction of clean and resource-efficient technologies.  The world will still rely on fossil fuels although other non-fossil fuels will be developed at the same time to “balance” the need as in the A1B scenario.  In motion and happening right now is the development of other non-fossil fuels while at the same time relying on fossil fuels to try to bring balance.  As in the B1 scenario, it is rather easy to introduce clean and resource-efficient technologies on a global scale.  Also, we can well see that we are already in the information age.

What key uncertainties (climate forcings and feedbacks) would exist for these scenarios as a whole or for specific ones individually?  Most probably, key uncertainties would exist for the A1F1, A1T, A2, and B2 scenarios to occur in the next 100 years.  The world will not just depend on fossil fuels within the next 100 years as evident from scientist present designing of hybrid fuels for automobiles.  On the flip side of that, it is highly unlikely that we will actually go completely with non-fossil fuel energy sources within the next 100 years.  Furthermore, we are living in a global village; thus, local or regional solutions will not work. 

Simply stated, A1F1 is most unlikely to happen within the next 100 years because its emphasis is on fossil fuels, but new cleaner non-fossil fuels are being developed.  Also, it is most improbable of A1T happening because a non-fossil energy source solution is ideal, but not realistic.  Non-fossil fuels will take more than the projected time to gradually take place of fossil fuels.  Most likely, it will take over 100 years to have non-fossil fuels totally replace fossil ones.  A2 most likely will not occur because its emphasis is on a world of independently operating and self-reliant nations.  We live in a global village, and the current warming and climate change issue is global.  Thus, working independently doesn’t work.  In a 100 year time span, B2 will also probably fail to occur because its emphasis is on local rather than global solutions to economic, social, and environmental stability.  Again, we live in a global village and the present warming and climate change is a global problem.  Therefore, solutions on the local level aren’t going to be successful either.  Also, as a world community, we are slow to accept more sustainable types of approaches to energies.  For example, an international agreement known as the Kyoto Protocol has been negotiated to reduce greenhouse gas emissions, but the US is not participating in it.  However, as mentioned earlier, A1B and B1 will probably work because A1B emphasizes balance on all resources, which is what we see now, and B1 because it is possible to introduce clean and resource-efficient technologies globally, which this scenario encompasses.  http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf

As a whole, uncertainties exist for these emission scenarios because projecting future emissions differs from other types of prediction that scientists make.  Many natural systems, such as planetary motions, are governed by well-understood physical natural laws.  A third category includes systems to which the concept of governing laws expressed by mathematical equations is not applicable (Gaffin, 2002).  For these systems, the driving forces change over time, sometimes radically, making prediction of specific outcomes a speculative effort.  Many social, political, and economic science systems would fall into this category.  Future anthropogenic emissions are a function of such socioeconomic systems and, as a result, are inherently unpredictable.  The National Academies Press states that although projections of future population are thus readily available for use in emissions models, long-term projections for the other key socioeconomic factors that drive emissions are generally not available, and they are unpredictable.  All the driving forces not only influence CO2 emissions, but also the emissions of other GHGs.  Therefore, uncertainties for these scenarios exist.  http://www.nap.edu/openbook.php?record_id=11175&page=109

Climate Forcings and Feedbacks

Climate Forcings and Feedbacks

For convenience and clarity, climate scientists separate things that affect climate change into two categories, forcings and feedbacks.  Radiative forcing is generally defined as the change in net irradiance between different layers of the atmosphere.  It is a way to quantify an energy imbalance imposed on the climate system either externally or by human activities.  Climate forcings are different factors that affect the Earth's climate.  These "forcings" drive or "force" the climate system to change, according to the National Oceanic and Atmospheric Administration (NOAA).  There are natural forcings and man-made forcings.  A positive forcing (more incoming energy) tends to warm the system, while a negative forcing (more outgoing energy) tends to cool it.  Climate feedbacks are processes that change as a result of a change in forcing, and cause additional climate change.  A feedback that increases an initial warming is called a 'positive feedback.’  A feedback that reduces an initial warming is a 'negative feedback.'

The forcings that were probably the most important during the last millennium were: changes in the output of energy from the sun, volcanic eruptions, and changes in the concentration of greenhouse gases in the atmosphere.  The National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies’ (GISS) graph images of the radiative forcings and the net forcings shows the changes in effectiveness of the main radiative forcings since 1880.  In the radiative forcings graph image, greenhouse gases are shown to have the greatest sustained positive forcing on the climate system.  Stratospheric aerosols from volcanic eruptions can also have a strong, negative cooling influence, but it is very short term.  There is a small influence of solar irradiance changes since 1880.  However, the indirect cooling impact of the release of man-made aerosols is also having a significant impact.  In the NASA GISS image that shows the overall Net Forcing since 1880, one can clearly see the trend toward the positive, which is clearly due to the increasing amount of well-mixed greenhouse gases into the Earth's atmosphere.  (http://data.giss.nasa.gov/modelforce/)

As the PBS Global Climate Change webpage stated, “…the National Academies examined the knowledge regarding the climate forcings associated with gases, aerosols, land use, and solar variability and to identify relevant research needs.”  Solar irradiance, aerosols, dust, smoke, and soot are examples of forcings occurring today.  Clouds, the carbon cycle, ocean circulation, precipitation, and sea level rise are examples of specific feedbacks.

Aerosols, dust, smoke, and soot is the forcings category that is prevalent here in Las Vegas.  These come from both human and natural sources.  They also have very different effects on climate.  Sulfate aerosols, which result from burning coal, biomass, and volcanic eruptions, tend to cool the Earth.  The reason that aerosols is more prevalent here in Vegas is because of the big coal mining industry here and the constant flux of people coming here and emitting poisonous gas fumes from their vehicles.  Basically, it is because of the overproduction of fossil fuels.  Blackstone Group LP, NV Energy, and White Pine Energy Associates are all energy giants that have coal-fired power plants here in Nevada. 

As the Global Climate Change articles stated, “Increasing industrial emissions of sulfates is believed to have caused a cooling trend in the Northern Hemisphere from the 1940s to the 1970s.  But other kinds of particles have the opposite effect.  The global distribution of aerosols has only been tracked for about a decade from the ground and from satellites, but those measurements cannot yet reliably distinguish between types of particulates.  So aerosol forcing is another substantial uncertainty in predictions of future climate.”

Currently, natural processes such as the carbon cycle remove about half of each year's human carbon dioxide emissions from the atmosphere, although this varies a bit year to year according to the Global Climate Change article.  However, the forcings is causing loss of carbon from terrestrial ecosystems, leading to an increase of atmospheric carbon dioxide levels.  Desertification is the degradation of land in dry lands caused by a variety of factors, such as climate change and human activities and it is one of the most significant global environmental problems, according to Helmut Geist.  The “Biological Feedbacks in Global Desertification” article stated that desertification is a consequence of global warming in some environments.  Desert soils, which Las Vegas is nothing but desert, contain little humus, and support little vegetation.  As a result, transition to desert ecosystems is typically associated with excursions of carbon.  In the article by Nature News, “Greenhouse effect has 'significantly dried' the western United States”, it stated that snowpack in mountain ranges such as the Rockies is diminishing, average minimum temperatures are rising, and spring run-off in major rivers such as the Colorado river is happening earlier.  All these changes seem set to make dry summers even harsher for residents of thirsty cities such as Las Vegas in Nevada.  Therefore, there is a serious concern in Las Vegas that there is an unbalance in carbon dioxide.  As the Global Climate change article stated, “There is also some evidence that the ability of the Earth system to continue absorbing carbon may decline as the world warms, leading to faster accumulation in the atmosphere.”  This seems to be the case here in Las Vegas.

The resources I have located to help me and my students understand climate forcings and feedbacks are:

Global Warming: The Physics of the Greenhouse Effect  video

This video segment adapted from NOVA/FRONTLINE examines the greenhouse effect, its role in keeping Earth habitable, and the industrial changes that have led to an increase in the planet's average temperature

http://www.teachersdomain.org/asset/phy03_vid_greenhouse2/

Global Warming: Carbon Dioxide and the Greenhouse Effect  video

This video segment adapted from NOVA/FRONTLINE demonstrates the physical property of carbon dioxide that causes the greenhouse effect

http://www.teachersdomain.org/asset/phy03_vid_co2/

Global Warming?

Students examine the issue of global warming.  They calculate how much carbon dioxide all the machines they use produce in one day.

Lesson Plan for Grades 9-12

http://www.teachersdomain.org/resource/tdc02.sci.life.eco.lp_co2globalwarm/

Speaking Your Mind About Global Warming

In this media-rich student activity, learn about the causes and impacts of global warming, as well as potential solutions, and then plan to produce a video response to this pressing issue.

http://www.teachersdomain.org/resource/ayv09.sci.ess.climate.saheat/

Global Climate Change: Understanding the Greenhouse Effect  Lesson Plan

Students study past climate change, explore the effect of greenhouse gases on Earth's atmosphere today, and consider human impact on global warming.

http://www.teachersdomain.org/resource/ess05.sci.ess.watcyc.lp_global1/

Global Warming and the Greenhouse Effect  video

This video segment from Race to Save the Planet: "Only One Atmosphere" discusses the greenhouse effect and global warming

http://www.teachersdomain.org/asset/tdc02_vid_greenhouse/

 

A Global Journey

Source: NPR: Climate Connections60.00Interactive/Online Activity

Investigate the roots and hazards of climate change while exploring this interactive world map by topic or by region. Learn about the causes and effects of global warming, the search for solutions and what humans can do to remedy the problem

http://www.pbs.org/teachers/connect/resources/6252/

Asia and Africa: Living on the Edge

Source: FRONTLINE/World60.00Video

Uncover the devastating effects of climate change in Asia and Africa. Focus on the melting Himalayan glaciers, which feed the region's great rivers, drought-stricken Africa and the warming waters of the South East Atlantic

http://www.pbs.org/teachers/connect/resources/6390/

Research resources:

Schlesinger, W. H.; Reynolds, J. F.; Cunningham, G. L.; Huenneke, L. F.; Jarrell, W. M.; Virginia, R. A.; Whitford, W. G. (1990).  "Biological Feedbacks in Global Desertification".  Science 247 (4946): 1043.  

(Bibcode 1990Sci...247.1043S.  doi:10.1126/science.247.4946.1043. PMID 17800060)

Which Web 2.0 tool did I explore, and how might it be used in the classroom to promote communication and/or reflection?

Which Web 2.0 tool did I explore, and how might it be used in the classroom to promote communication and/or reflection? 

In this class, I explored and signed up for the Diigo Web 2.0 tool.  It is used for online bookmarking, highlighting and sticky notes for your readings, it is used for group based collaborative research, and to collect and organize anything anywhere. So, it definitely can be used in the classroom for a collaborative group project in which students have to do researching.  The Diigo allows users to collect, highlight, access, and share a variety of information on a variety of devices.  I certainly see the idea and not so distant future in which an annotated bibliography is not needed.  Why go through all the trouble when you can just use the Diigo Web 2.0 tool?

How do NASA, STEM, & PBL meet the needs of 21st century Education?

First of all, what exactly is 21^st century education?  The article, “What is 21^st Century Education” stated that  it is an authentic education system that addresses the “whole child”, the “whole person”, and does not limit its professional development and curriculum design to workplace readiness.  It also stated that the 21^st century skills learned through its curriculum, which is interdisciplinary, integrated, project-based, and more, include and are learned within a project-based curriculum by utilizing the seven survival skills advocated by Tony Wagner in his book, The Global Achievement Gap:

·   Critical Thinking and Problem Solving

·   Collaboration across Networks and Leading by Influence

·   Agility and Adaptability

·   Initiative and Entrepreneurialism

·   Effective Oral and Written Communication

·   Accessing and Analyzing Information·    Curiosity and Imagination

So then, to the main question.  How do NASA, STEM, and PBL meet the needs of 21^st century education?  Well, the framework from the Partnership for 21^st Century Skills addresses the rapid shift of the world, and it has many skills that are directly related to helping students take control of their learning and keep on learning.  The NASA, PBL, and STEM article stated that because our world changes so rapidly and problems are constantly evolving, our students need to know how to face problems and solve them.  Understanding the process of problem solving using information that is constantly changing will make them better able to meet the needs of the future workforce.  The article said these skills include being able to

• Use various types of reasoning.
• Effectively analyze and evaluate evidence, arguments, claims, and beliefs.
• Analyze and evaluate major alternative points of view.
• Synthesize and make connections between information and arguments.
• Interpret information and draw conclusions.
• Reflect critically on learning experiences and processes.
• Articulate thoughts and ideas effectively using oral, written, and nonverbal communication skills.
• Utilize multiple media and technologies, and know how to judge their effectiveness.

The article affirmed that STEM is a strategy that connects all of these skills, and NASA and PBS are some of the organizations promoting STEM education.  STEM is a student-centered and problem based methodology that integrates all the sciences together: technology, math, science, and engineering.  I am apt in math and technology, and I know some science; however, I would have to take some classes for engineering, which is something I was thinking about doing anyway. 

PBL projects are content addressed layered with 21st century skills, driving questions, products, procedures, and evaluation.  This article certainly answered my questions as to the meaning of these various acronyms. 

Moreover, NASA, STEM, and PBL goals are aligned with and meet the aspirations and mission of 21^st century education, namely, providing an educational bridge that addresses the student as a “whole” person.