Image Reflecting Seriousness ClimateChange

NASAs latest Climate Change Mission- Glory Departs Feb 23,

The NASA satellite Glory is set to launch into the Earths Atmosphere.  The Glory Launch will further Climatologist study of Airborne Particles (Aerosols) and how they affect the the Earths Climate.  They will be studying the ubiquitous particles (existing or being everywhere, especially at the same time; omnipresent) that directly influence the Climate by absorbing and reflecting the Sun's Radiation.

The Aerosol Particles they will be examining are-" few nanometers, less than the width of the smallest viruses, to several tens of micrometers, about the diameter of human hair" The Aerosols are Created by: Aerosols, Gases that lead to Aerosol formation, Fossil Fuel Exhaust Gases, and Natural causes. -- the amount of energy entering and exiting Earth's atmosphere. An accurate measurement of these impacts is important in order to anticipate future changes to our climate and how they may affect human life.

Godspeed and Good Luck to all those involved.

Scott's Contracting
scottscontracting@gmail.com
http://www.stlouisrenewableenergy.blogspot.com
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Climatologists have known for decades that airborne particles called aerosols can have a powerful impact on the climate. However, pinpointing the magnitude of the effect has proven challenging because of difficulties associated with measuring the particles on a global scale.

Soon a new NASA satellite -- Glory -- should help scientists collect the data needed to provide firmer answers about the important particles. In California, engineers and technicians at Vandenberg Air Force Base are currently prepping Glory for a Feb. 23 launch.

Aerosols, or the gases that lead to their formation, can come from vehicle tailpipes and desert winds, from sea spray and fires, volcanic eruptions and factories. Even lush forests, soils, or communities of plankton in the ocean can be sources of certain types of aerosols.

The ubiquitous particles drift in Earth's atmosphere, from the stratosphere to the surface, and range in size from a few nanometers, less than the width of the smallest viruses, to several tens of micrometers, about the diameter of human hair.

The particles can directly influence climate by reflecting or absorbing the sun's radiation. In broad terms, this means bright-colored or translucent aerosols, such as sulfates and sea salt aerosols, tend to reflect radiation back towards space and cause cooling. In contrast, darker aerosols, such as black carbon and other types of carbonaceous particles, can absorb significant amounts of light and contribute to atmospheric warming.

Research to date suggests that the cooling from sulfates and other reflective aerosols overwhelms the warming effect of black carbon and other absorbing aerosols. Indeed, the best climate models available show that aerosol particles have had a cooling effect that has counteracted about half of the warming caused by the build-up of greenhouse gases since the 1880s.

"However, the models are far from perfect," said Glory Project Scientist Michael Mishchenko, a senior scientist at the Goddard Institute for Space Studies (GISS). "The range of uncertainty associated with the climate impact of aerosols is three or four times that of greenhouse gases," he said.

In comparison to greenhouse gases, aerosols are short-lived, and dynamic -- making the particles much harder to measure than long-lived and stable carbon dioxide. Aerosols usually remain suspended in the atmosphere for just a handful of days. Complicating matters, the particles can clump together to form hybrids that are difficult to distinguish.

In addition to scattering and absorbing light, aerosols can also modify clouds. They serve as the seeds of clouds, and can also affect cloud brightness and reflectivity, how long clouds last, and how much they precipitate. Reflective aerosols, like sulfates, for example, tend to brighten clouds and make them last longer, whereas black carbon from soot generally has the opposite effect.

Still, much remains unknown about aerosols and clouds. How do aerosols other than sulfates and black carbon affect clouds? How do aerosol impacts differ in warm and cold environments? Can infusions of aerosols near clouds spark self-reinforcing feedback cycles capable of affecting the climate?

The climate impact of clouds remains one of the largest uncertainties in climate science because of such unanswered questions. Some models suggest a mere 5 percent increase in cloud reflectivity could compensate for the entire increase in greenhouse gases from the modern industrial era, while others produce quite different outcomes.

Such unresolved issues prompted the Intergovernmental Panel on Climate Change (IPCC) to list the level of scientific understanding about aerosols as "low" in its last major report. Of the 25 climate models included by the IPCC in the Fourth Assessment Report, only a handful considered the scattering or absorbing effects of aerosol types other than sulfates.

"And less than a third of the models included aerosol impacts on clouds, even in a limited way, and those that did only considered sulfates," said Mian Chin, a physical scientist at NASA's Goddard Space Flight Center who specializes in modeling aerosols.

Glory, which contains an innovative aerosol-sensing instrument called the Aerosol Polarimetry Sensor (APS), aims to change this. By more accurately identifying a broad suite of aerosol types -- such as salt, mineral dust and smoke -- the instrument should help climatologists fill in key gaps in climate models.

While other NASA instruments -- including ground, aircraft, and satellite-based instruments -- have studied aerosols in the past, APS is NASA's first satellite-based instrument capable of measuring the polarization, the orientation of light-wave vibrations.

Raw sunlight, explained Mishchenko, is unpolarized. This means the waves oscillate in an unpredictable, random fashion as they move through space -- much like a rope would wiggle about if it had two people flapping its ends up and down in no particular pattern.

When light waves pass through certain types of filters called polarizers the waves are forced into a more ordered form. Imagine that wobbling rope trying to pass throw a narrow slit in a fence: only the waves vibrating at a certain angle could make it through. The result is polarized light, or light for which the waves only oscillate at specific angles. The surface of glass, sunglasses, even clouds of aerosol particles can polarize light.

APS's ability to measure the polarization of light scattered by aerosols and clouds is the key strength of the instrument. Other NASA satellite instruments have measured aerosols, but such instruments have typically done so by looking at the intensity of light -- the amplitude of the light waves -- not their polarization.

Yet, ground and aircraft-based studies, particularly those conducted with an aircraft instrument called the Research Scanning Polarimeter, which is quite similar to APS, show that polarized light contains the most information about aerosol features. "Earlier instruments can approximate the abundance of aerosol in general terms, but they leave much to be desired if you're trying to sort out the shape and composition of the particles," said APS Instrument Scientist Brian Cairns, also of GISS.

These scanning electron microscope images, which are not at the same scale, show the wide variety of aerosols shapes. From left to right: volcanic ash, pollen, sea salt, and soot. Credit: USGS, UMBC, Arizona State University

Large, spherical particles -- sea salt, for example -- leave a very different imprint on light in comparison to smaller and more irregularly-shaped particles such as black carbon. As a result, much like forensic scientists might study the details of blood droplets at a crime scene to reconstruct what happened, climatologists using Glory data will look to the polarization state of scattered light to work backwards and deduce the type of aerosol that must have scattered it.

Glory will not be the first Earth-observing satellite instrument to study polarization. French instruments that launched in 1996 and 2002 have as well, but the APS promises to be far more accurate and will look at the same particles from many more angles.

Nonetheless, interpreting Glory's APS data will be an extremely complex task. The mission will provide such a vast amount of new polarization data about aerosols that, in order to make sense of it, scientists will first have to validate APS science products with ground-based sensors scattered around the globe. Likewise, they will have to adapt and update mathematical techniques developed for an aircraft instrument to ensure they work well in a space environment.

All of this will take some time to refine and perfect. Mishchenko's team expects to release preliminary results as soon as possible after Glory launches, but he also expects to release improved and enhanced versions of Glory's APS data products over time.

A great deal of work lies ahead of Glory's science team and the aerosol science community more broadly, but the mission has the potential to produce profound advancements in understanding the perplexing particles. "Glory has the potential to offer a critical view of aerosols that we have never had from space before," said Glory's Deputy Project Scientist Ellsworth Welton.

NASAs Climate Change Prediction

How Much More Will Earth Warm?

To further explore the causes and effects of global warming and to predict future warming, scientists build climate models—computer simulations of the climate system. Climate models are designed to simulate the responses and interactions of the oceans and atmosphere, and to account for changes to the land surface, both natural and human-induced. They comply with fundamental laws of physics—conservation of energy, mass, and momentum—and account for dozens of factors that influence Earth's climate.

Though the models are complicated, rigorous tests with real-world data hone them into powerful tools that allow scientists to explore our understanding of climate in ways not otherwise possible. By experimenting with the models—removing greenhouse gases emitted by the burning of fossil fuels or changing the intensity of the Sun to see how each influences the climate—scientists use the models to better understand Earth's current climate and to predict future climate.

The models predict that as the world consumes ever more fossil fuel, greenhouse gas concentrations will continue to rise, and Earth's average surface temperature will rise with them. Based on a range of plausible emission scenarios, average surface temperatures could rise between 2°C and 6°C by the end of the 21st century.

Model simulations by the Intergovernmental Panel on Climate Change estimate that Earth will warm between two and six degrees Celsius over the next century, depending on how fast carbon dioxide emissions grow. Scenarios that assume that people will burn more and more fossil fuel provide the estimates in the top end of the temperature range, while scenarios that assume that greenhouse gas emissions will grow slowly give lower temperature predictions. The orange line provides an estimate of global temperatures if greenhouse gases stayed at year 2000 levels. (©2007 IPCC WG1 AR-4.)

Climate Feedbacks

Greenhouse gases are only part of the story when it comes to global warming. Changes to one part of the climate system can cause additional changes to the way the planet absorbs or reflects energy. These secondary changes are called climate feedbacks, and they could more than double the amount of warming caused by carbon dioxide alone. The primary feedbacks are due to snow and ice, water vapor, clouds, and the carbon cycle.

Snow and ice

Perhaps the most well known feedback comes from melting snow and ice in the Northern Hemisphere. Warming temperatures are already melting a growing percentage of Arctic sea ice, exposing dark ocean water during the perpetual sunlight of summer. Snow cover on land is also dwindling in many areas. In the absence of snow and ice, these areas go from having bright, sunlight-reflecting surfaces that cool the planet to having dark, sunlight-absorbing surfaces that bring more energy into the Earth system and cause more warming.

Canada's Athabasca Glacier has been shrinking by about 15 meters per year. In the past 125 years, the glacier has lost half its volume and has retreated more than 1.5 kilometers. As glaciers retreat, sea ice disappears, and snow melts earlier in the spring, the Earth absorbs more sunlight than it would if the reflective snow and ice remained. (Photograph ©2005 Hugh Saxby.)

Water Vapor

The largest feedback is water vapor. Water vapor is a strong greenhouse gas. In fact, because of its abundance in the atmosphere, water vapor causes about two-thirds of greenhouse warming, a key factor in keeping temperatures in the habitable range on Earth. But as temperatures warm, more water vapor evaporates from the surface into the atmosphere, where it can cause temperatures to climb further.

The question that scientists ask is, how much water vapor will be in the atmosphere in a warming world? The atmosphere currently has an average equilibrium or balance between water vapor concentration and temperature. As temperatures warm, the atmosphere becomes capable of containing more water vapor, and so water vapor concentrations go up to regain equilibrium. Will that trend hold as temperatures continue to warm?

The amount of water vapor that enters the atmosphere ultimately determines how much additional warming will occur due to the water vapor feedback. The atmosphere responds quickly to the water vapor feedback. So far, most of the atmosphere has maintained a near constant balance between temperature and water vapor concentration as temperatures have gone up in recent decades. If this trend continues, and many models say that it will, water vapor has the capacity to double the warming caused by carbon dioxide alone.

Clouds

Closely related to the water vapor feedback is the cloud feedback. Clouds cause cooling by reflecting solar energy, but they also cause warming by absorbing infrared energy (like greenhouse gases) from the surface when they are over areas that are warmer than they are. In our current climate, clouds have a cooling effect overall, but that could change in a warmer environment.

Clouds can both cool the planet (by reflecting visible light from the sun) and warm the planet (by absorbing heat radiation emitted by the surface). On balance, clouds slightly cool the Earth. (NASA Astronaut Photograph STS31-E-9552 courtesy Johnson space Center Earth Observations Lab.)

If clouds become brighter, or the geographical extent of bright clouds expands, they will tend to cool Earth's surface. Clouds can become brighter if more moisture converges in a particular region or if more fine particles (aerosols) enter the air. If fewer bright clouds form, it will contribute to warming from the cloud feedback.

See Ship Tracks South of Alaska to learn how aerosols can make clouds brighter.

Clouds, like greenhouse gases, also absorb and re-emit infrared energy. Low, warm clouds emit more energy than high, cold clouds. However, in many parts of the world, energy emitted by low clouds can be absorbed by the abundant water vapor above them. Further, low clouds often have nearly the same temperatures as the Earth's surface, and so emit similar amounts of infrared energy. In a world without low clouds, the amount of emitted infrared energy escaping to space would not be too different from a world with low clouds.

Clouds emit thermal infrared (heat) radiation in proportion to their temperature, which is related to altitude. This image shows the Western Hemisphere in the thermal infrared. Warm ocean and land surface areas are white and light gray; cool, low-level clouds are medium gray; and cold, high-altitude clouds are dark gray and black. (NASA image courtesy GOES Project Science.)

High cold clouds, however, form in a part of the atmosphere where energy-absorbing water vapor is scarce. These clouds trap (absorb) energy coming from the lower atmosphere, and emit little energy to space because of their frigid temperatures. In a world with high clouds, a significant amount of energy that would otherwise escape to space is captured in the atmosphere. As a result, global temperatures are higher than in a world without high clouds.

If warmer temperatures result in a greater amount of high clouds, then less infrared energy will be emitted to space. In other words, more high clouds would enhance the greenhouse effect, reducing the Earth's capability to cool and causing temperatures to warm.

See Clouds and Radiation for a more complete description.

Scientists aren't entirely sure where and to what degree clouds will end up amplifying or moderating warming, but most climate models predict a slight overall positive feedback or amplification of warming due to a reduction in low cloud cover. A recent observational study found that fewer low, dense clouds formed over a region in the Pacific Ocean when temperatures warmed, suggesting a positive cloud feedback in this region as the models predicted. Such direct observational evidence is limited, however, and clouds remain the biggest source of uncertainty--apart from human choices to control greenhouse gases—in predicting how much the climate will change.

The Carbon Cycle

Increased atmospheric carbon dioxide concentrations and warming temperatures are causing changes in the Earth's natural carbon cycle that also can feedback on atmospheric carbon dioxide concentration. For now, primarily ocean water, and to some extent ecosystems on land, are taking up about half of our fossil fuel and biomass burning emissions. This behavior slows global warming by decreasing the rate of atmospheric carbon dioxide increase, but that trend may not continue. Warmer ocean waters will hold less dissolved carbon, leaving more in the atmosphere.

About half the carbon dioxide emitted into the air from burning fossil fuels dissolves in the ocean. This map shows the total amount of human-made carbon dioxide in ocean water from the surface to the sea floor. Blue areas have low amounts, while yellow regions are rich in anthropogenic carbon dioxide. High amounts occur where currents carry the carbon-dioxide-rich surface water into the ocean depths. (Map adapted from Sabine et al., 2004.)

See The Ocean's Carbon Balance on the Earth Observatory.

On land, changes in the carbon cycle are more complicated. Under a warmer climate, soils, especially thawing Arctic tundra, could release trapped carbon dioxide or methane to the atmosphere. Increased fire frequency and insect infestations also release more carbon as trees burn or die and decay.

On the other hand, extra carbon dioxide can stimulate plant growth in some ecosystems, allowing these plants to take additional carbon out of the atmosphere. However, this effect may be reduced when plant growth is limited by water, nitrogen, and temperature. This effect may also diminish as carbon dioxide increases to levels that become saturating for photosynthesis. Because of these complications, it is not clear how much additional carbon dioxide plants can take out of the atmosphere and how long they could continue to do so.

The impact of climate change on the land carbon cycle is extremely complex, but on balance, land carbon sinks will become less efficient as plants reach saturation, where they can no longer take up additional carbon dioxide, and other limitations on growth occur, and as land starts to add more carbon to the atmosphere from warming soil, fires, and insect infestations. This will result in a faster increase in atmospheric carbon dioxide and more rapid global warming. In some climate models, carbon cycle feedbacks from both land and ocean add more than a degree Celsius to global temperatures by 2100.

Emission Scenarios

Scientists predict the range of likely temperature increase by running many possible future scenarios through climate models. Although some of the uncertainty in climate forecasts comes from imperfect knowledge of climate feedbacks, the most significant source of uncertainty in these predictions is that scientists don't know what choices people will make to control greenhouse gas emissions.

The higher estimates are made on the assumption that the entire world will continue using more and more fossil fuel per capita, a scenario scientists call "business-as-usual." More modest estimates come from scenarios in which environmentally friendly technologies such as fuel cells, solar panels, and wind energy replace much of today's fossil fuel combustion.

It takes decades to centuries for Earth to fully react to increases in greenhouse gases. Carbon dioxide, among other greenhouse gases, will remain in the atmosphere long after emissions are reduced, contributing to continuing warming. In addition, as Earth has warmed, much of the excess energy has gone into heating the upper layers of the ocean. Like a hot water bottle on a cold night, the heated ocean will continue warming the lower atmosphere well after greenhouse gases have stopped increasing.

These considerations mean that people won't immediately see the impact of reduced greenhouse gas emissions. Even if greenhouse gas concentrations stabilized today, the planet would continue to warm by about 0.6°C over the next century because of greenhouses gases already in the atmosphere.

See Earth's Big Heat Bucket, Correcting Ocean Cooling, and Climate Q&A: If we immediately stopped emitting greenhouse gases, would global warming stop? to learn more about the ocean heat and global warming.

Next Page: How Will Global Warming Change Earth? -- Scott's Contracting scottscontracting@gmail.com http://www.stlouisrenewableenergy.blogspot.com http://www.stlouisrenewableenergy.com scotty@stlouisrenewableenergy.com