[Note from the editor: This will be the first in a series of blog entries that will focus on introductory topics in climate dynamics and modeling, and will be a great insight into the current understanding of the science.]

The atmosphere is the most important component of Earth’s climate system. An introduction to atmospheric composition, properties and circulation is given in an easy-to-read, freely available, online book from the Université Catholique de Louvain.

Dry air (i.e., without its water vapor) is mainly composed of nitrogen (78% in volume), oxygen (21%), argon (0.93%), carbon dioxide (0.038%) and various trace constituents such as neon, helium, methane and krypton. Additionally, highly variable amounts of water vapor are also present, from approximately 0% in the coldest parts of the atmosphere to 5% in moist regions.

The atmospheric pressure is at its maximum at the Earth’s surface and decreases with height, a condition that arises from the Earth’s atmosphere being in hydrostatic balance. The temperature in the lowest part of the atmosphere, or troposphere (roughly the first 10 km) generally decreases with height, and the rate of this decrease is called the lapse rate. The lapse rate is an important quantity because it determines the vertical stability of the atmosphere. Low values of lapse rate mean that the atmosphere is very stable, which will inhibit clouds and precipitation from forming. With higher lapse rate values (temperature decreasing faster with height), the atmospheric stability decreases, leading to a greater chance for clouds, convection, and precipitation.

Above the troposphere, the stratosphere extends to about 50 km height. Here the temperature increases with height. Above the stratosphere is the mesosphere, where temperature decreases strongly with height until the thermosphere is reached at around 80 km, where temperature then increases with height once more. The increasing/decreasing of temperature above 10 km is strongly influenced by the absorption of solar radiation by atmospheric constituents and by chemical reactions. In particular, the warming in the high stratosphere is mostly due to the absorption of ultraviolet radiation by a layer of ozone, which protects life on Earth from this dangerous radiation.

The atmospheric humidity has maximum values in the lower layers of the troposphere and decreases with height. This is due to the fact that the major source of water vapor in the atmosphere is evaporation at the surface. Also, warmer air (i.e. air close to the surface) is able to hold larger amounts of water before becoming saturated than can higher, colder layers. Saturation leads to the formation of clouds and, eventually, precipitation.

At the Earth’s surface, the temperature is highest closer to the equator because of the higher incoming solar radiation year-round. The global distribution of the surface temperature is also influenced by atmospheric and oceanic heat transport (for example the Atlantic Gulf Stream keeps Northern Europe comparatively warm) and the topography, among other processes.

The large-scale atmospheric circulation is mainly driven by changes in density and by the Earth’s rotation. The air at the equator is less dense due to its higher temperature and tends to rise upward before being transported poleward at high altitudes. This motion is compensated for by an equator-ward displacement of air at the surface. The two cells (one in each hemisphere) driven by the upward movement at the equator (Hadley cells) terminate with a downward moving branch at a latitude of about 30°. At the surface the Earth’s rotation deflects the flow coming from mid-latitudes to the Equator towards the right in the Northern Hemisphere and towards the left in the Southern, called the Coriolis Force. This is the reason for easterly trade winds in tropical regions.

The equator-bound air of the two hemispheres meet close to the equator in a band called the Intertropical Convergence Zone (ITCZ) resulting in colliding air and rising motion, which causes heavy precipitation. Because of the geometry of the continents, the ITCZ is located around 5°N and shifts throughout the seasons. Further north (and south) from the equator, weather regimes are dominated by westerly winds and Ferrel cells, mirror images of Hadley cells.

Satellite image of the ITCZ in the Western Hemisphere

The large-scale atmospheric circulation has a strong influence on precipitation. Along the ITCZ, the cooling of warm, moist surface air during its rising motion leads to condensation and heavy precipitation in this area. In contrast, sinking motion in the subtropics is associated with the presence of dry air and low precipitation rates. For this reason the majority of the large deserts on Earth are located in the sub-tropical belt.

Keep in mind that broad-scale rising motion is associated with clouds and precipitation, while broad-scale sinking motion is associated with clear skies and dryness.

The presence of land surfaces has a critical role in the monsoon circulation. A monsoon is a seasonal reversal of surface winds caused by the differential heating of a land mass and its adjacent ocean. The monsoon strongly affects the precipitation over subtropical continents. During the winter monsoon, the inflow of dry continental air is associated with low precipitation. On the other hand, the summer brings moist air from the ocean inducing heavy rainfall for months at a time.

The land topography also plays an important role in precipitation as it can generate vertical motion when air masses collide with mountain boundaries. Where upward movement of moist air is topographically induced, massive precipitation can occur. If downward motion of dry air is generated on the lee side of nearby mountains, the precipitation will be low.

Over the oceans in the mid-latitudes, precipitation in winter is mainly due to low-pressure systems called cyclones which tend to follow a common path at about 45°N in the Pacific and the Atlantic along the jet stream. Since the Earth is unevenly heated at the equator vs. the poles, cyclones can be thought of as a way for masses of cold air from the poles to mix with masses of warmer air from the equator in an attempt to restore thermal equilibrium. The path that cyclones tend to follow in mid-latitudes, called their storm-track, results in considerable precipitation in these regions, either in the form of rain, snow, or mixed precipitation.

Reference:

Goosse H., P.Y. Barriat, W. Lefebvre, M.F. Loutre and V. Zunz, (2012). Introduction to climate dynamics and climate modeling. Online textbook available at http://www.climate.be/textbook

From 2004 to 2008, Google searches in the Eastern U.S. with the word hurricane and searches with the words National Hurricane Center were examined in terms of both volume and region. As expected, the spikes in search volume appeared in yearly cycles, peaking during the North Atlantic Hurricane Season in late summer and early fall (see figure below). Years that had especially high-impact hurricanes (e.g. Frances in 2004, Katrina in 2005, Ike in 2008) saw the greatest spikes in search volume.

Regional analysis of Google searches also showed a strong correlation with each hurricane forecast cone (projected path) from the National Hurricane Center, even up to five days in advance of a forecasted landfall. This demonstrates the incredible influence of these forecast products on the public. While this influence usually has a positive effect by preparing the potentially-affected population for evacuation or storm-readiness, it can also have a negative impact if the hurricane fails to materialize where initially forecasted. The result is a “false alarm” and reduced confidence of the public in future forecasts. This study reaffirms that avoiding a “Boy Who Cried Wolf” scenario is more important than ever in today’s Information Age.

Researchers also found heavy search traffic for words like traffic, evacuation, and gas prices in conjunction with searches for hurricane, suggesting the relevance and need for very specific emergency management information on very small regional scales in advance of impending hurricanes. Local weather stations and National Weather Service offices can use these up-to-the-minute Google search data to identify areas that they might not have covered yet that the public still wants to know about. It is obvious that the availability of this data from Google stretches far beyond just being a gimmick and can be used in real-time to save lives during landfalling hurricane events.

References:

Sherman-Morris, K., J. Senkbeil, and R. Carver. “Who’s Googling What?” Bulletin of the American Meteorological Society. Aug. 2011: 975-985. Print.

The U.S. Global Change Research Program (USGCRP) coordinates and integrates federal research on changes in the global environment and their implications for society. The USGCRP began as a presidential initiative in 1989 and was mandated by Congress in the Global Change Research Act of 1990 (P.L. 101-606) “to understand, assess, predict, and respond to human-induced and natural processes of global change.”

These activities led to major advances in several key areas including but not limited to:

• Observing and understanding short- and long-term changes in climate, the ozone layer, and land cover;
• Identifying the impacts of these changes on ecosystems and society;
• Estimating future changes in the physical environment, and vulnerabilities and risks associated with those changes; and
• Providing scientific information to enable effective decision making to address the threats and opportunities posed by climate and global change.

Their 2009 report stated that a central finding was that the vast majority of climate scientists agree that global warming is unequivocal and primarily human-induced. The report also identified widespread climate-related impacts that are occurring now in the United States and are expected to increase, including:

• Climate change is expected to stress water resources.
• Crop and livestock production increasingly will be challenged in a warmer climate.
• Risks to human health will increase due to heat stress, waterborne diseases, poor air quality, and diseases transmitted by insects and rodents.

They conclude that the future climate and its resulting impacts on society depend on choices made today. Even if societies substantially reduce their emissions of greenhouse gases, some changes are unavoidable due to millennium-scale processes in the atmosphere and oceans. Nonetheless, careful planning and assessment of climate change impacts will be important for effective mitigation and adaptation policies.

Their 2011 report states that the program intends to place greater emphasis on impacts, vulnerabilities, and on understanding the options for adapting to the changing climate as well as to continue support for activities that contribute to a better understanding of the Earth system, including observations, research and predictive modeling.

Their advances have been documented in numerous assessments commissioned by the program and have played prominent roles in international assessments such as those of the Intergovernmental Panel on Climate Change.

Program results, summarized in Our Changing Planet, can be downloaded for free at http://www.globalchange.gov/publications/our-changing-planet-ocp.

Los Angeles Air Pollution by Magazine.ucla.edu

CO₂ scrubbers have been developed but so far, all have been prohibitively expensive. The Journal of the American Chemical Society reports that researchers at the University of Southern California’s Loker Hydrocarbon Research Institute have developed an extraction method that has achieved some of the highest rates ever reported for removing carbon dioxide from the air. The method, which is low-cost and simple, involves use of a plastic-like substance dispersed in a sandy material called fumed silica. The technique allows the carbon dioxide to be used for recycling or to be isolated from the environment.

One the study’s researchers claims fumed silica is cheap to produce and can be used multiple times without losing efficiency. They claim the technique is more energy efficient and more chemically stable than existing extraction devices. The technique is expected to be released in the next 3 to 5 years.

Source

Voice of America, “New Discovery Promises Efficient Way to Recycle Carbon Dioxide Pollution,” (January 06, 2012). Taken from: http://www.voanews.com/english/news/-New-Discovery-Promises-Efficient-Way-to-Recycle-Carbon-Dioxide-Pollution-136861468.html

by Theurbn.com

Energy systems are vulnerable to climate change. Assessing the various scenarios that could occur is a great challenge, due to the number of climate variables and the interconnection between the various energy sectors. A review of the scientific literature on this topic that was just been published, helps understand the many implications of global warming for the energy sector. In addition to energy resources, climate change will likely affect supply, distribution, use and infrastructure in addition to cross-sector effects.

Energy resources are the primary energy available, such as fossil fuels stocks and renewable energy fluxes. Climate change may affect the hydrological cycle and, therefore, hydropower generation because it depends on water availability. The accessibility to wind power depends on weather conditions, in particular on the geographical distribution and variability of wind speed. Liquid biofuels are vulnerable to changes in climate variables (such as temperature, rainfall, CO₂ levels, drought, frost and storm frequencies) that affect crop used as raw materials to produce ethanol and biodiesel. Changing atmospheric water vapor content and cloud characteristics could affect solar energy resources and electricity generation from photovoltaic and concentrated solar power arrays. Energy production from ocean waves can be modified by wind changes. Although climate change will not directly affect oil and natural gas resources, it may affect producing areas (e.g., by melting permafrost use of this energy source can threaten the structural integrity of infrastructure built upon it).

by Greenhackz.com

Energy supply refers to the technologies used to convert primary energy resources into final energy sources used to meet specific services. Hourly, daily or seasonal variability of wind speeds significantly affects the energy produced from wind turbines making the production of wind power highly susceptible to changing wind patterns resulting from climate change. Increased air temperature can modify photovoltaic cell efficiency and reduce electrical generation from solar energy. Lower water availability caused by increased evaporation due to rising temperatures and lower precipitation levels can reduce crop productivity and energy production from liquid biofuels.

Alterations in the quantity and quality of water are the main way through which climate change could affect thermal power generation. Oil and gas production facilities in low-lying coastal areas and the outer continental shelf can be affected by sea level rise, storm intensity, wave regime, air and water temperature, precipitation patterns, extreme weather events, changes in CO₂ levels and ocean acidity. The possible increases in frequency and intensity of rainfall may lead to changes in river and groundwater levels and flooding, which could cause changes in coal quality and coal-handling.

The distribution of energy extends for thousands of kilometers and can therefore be exposed to weather phenomena that may cause transmission power line failures and affect gas transmission systems. These include extreme winds and ice loads, combined wind-on-ice loads, lightning strikes, conductor vibrations and galloping, avalanches, landslides, flooding, permafrost thawing and other extreme meteorological events. In addition, distribution systems are vulnerable to meteorologically-induced factors, such as falling trees and higher temperatures.

Climate change can affect energy use but will vary across regions. Higher temperatures imply lower demand for heating and higher demand for cooling. Therefore tropical regions will especially experience increased use of energy for cooling. Climate change can also affect the water and electricity demand in industries (for refrigeration) and in agriculture (for irrigation). Finally, changes in temperature will increase use of air conditioning in vehicles, and therefore increase the use of fuel.

The energy infrastructure, especially oil and gas related facilities that are situated in low-lying coastal areas will be more vulnerable to sea level rise and related coastal erosion as well as extreme weather events such as flooding and hurricanes. Inland structures also are vulnerable as there may be severe weather events and changes in water availability.

Last, cross-sectors will affect other economic and natural systems that will then affect the supply and demand for energy. The effects of climate change need to be assessed in an integrated way, including the many complex inter-relationships within the energy sector. The two main cross-sector affected by climate change are competition for water resources (in electricity generation, oil refining and irrigation of energy crops) and land competition (for biofuels production).

Despite energy being one of the key systems for social and economic development, its management often does not incorporate the effects of future climate variations in planning and operation. Assessing the vulnerabilities of energy systems and incorporating them into long-term energy planning and operation is imperative for the development of policies aiming to cope with climate change. Past experience on climate variability together with climate and energy system modeling are complementary ways to understand the vulnerability to climate change. To this end IEDRO collects and digitizes historic weather data.

Reference

Schaeffer, R., Szklo, A. S., Pereira de Lucena, A. F., Moreira Cesar Borba, B. S., Pupo Nogueira, L. P., Fleming, F. P., Troccoli, A., et al. (2011). Energy sector vulnerability to climate change: A review. Energy, 1-12. Elsevier Ltd. doi:10.1016/J.Energy.2011.11.056.

by www.Zedge.net

[UPDATED 6/23, 9:30 a.m.] Twenty years ago today, James E. Hansen testified before the Senate Energy Committee — in a room kept intentionally warm by committee staff — that the atmospheric buildup of carbon dioxide and other greenhouse gases from burning fossil fuels and forests was already perceptibly influencing Earth’s climate.

There’s a quote from the New York Times’ Andrew C. Revkin, dated June 23, 2008, memorializing a key 1988 turning point in the history of human-caused climate change. Dr. Hansen, then director of NASA’s Goddard Institute for Space Studies in New York City. Revkin added:

The video [shot by Revkin during a 2008 interview that is the subject of the article] begins with [Dr. Hansen's] explanation of a visual aid he created in 1988 with Jose Mendoza, an illustrator at Goddard in the days before PowerPoint: a pair of cardboard dice showing how humans were tipping the odds toward climate troubles. Notably, perhaps because of old glue, the paper black dots were falling off. (emphasis added)

The more I think about Dr. Hansen’s metaphor, the more impressed I am. In 1988, he was able to come up with a very simple explanation of how humans were affecting the climate–so simple that almost anyone could understand it. My profession is communications, and I can tell you from long experience, that’s not easy to do.

In addition to being simple, it’s a very accurate (perfect?) description of a scientific phenomenon that is becoming more and more obvious as time goes on, and the perfect response to those who (1) point to a remarkably cold or snowy day as proof that global warming does not exist or (2) (accurately) state that any short stretch of weather does not prove the climate is changing.  No, a short stretch of record hot weather does not prove anything, but we are loading the climate dice, and it’s exactly the type of weather that we will be seeing more and more of as time passes, because we have changed the odds and the “old normal” no longer applies.

I’d like to encourage everyone who shares my concern about global warming, and about the remarkably poor job most mass media are doing of communicating the issue, to bring up the topic of “loading the dice” as often as possible. It is simple, it is accurate, and there is not, to my knowledge, an easy and simple denier response. Regrettably, after all this time, many newspaper and broadcast journalists still do not get this most basic explanation of the effect of human-caused climate change on weather.

Source

Taken from: http://itsburning.blogspot.com/

West Nile Virus, a known disease threat to humans, was first observed to be carried by mosquitoes in the Midwestern United States in 1999. Since then, state and local governments have enacted mosquito abatement plans that involve large-scale spraying to stem the spread of the disease. While spraying can be lifesaving for humans, birds and animals, it can be fairly expensive. Therefore, in an effort to optimize mosquito spraying schedules, the state of Illinois turned to the Illinois State Water Survey in the 2000’s to develop a method of predicting when the rise of disease-carrying mosquitos might occur each year. A solution to the problem came from a climatologist.

Nancy Westcott and a team of supporting scientists at the Illinois State Water Survey analyzed recent climate datasets side-by-side with incidences of mosquito proliferation in Illinois. From this they developed a model that was able to retroactively pinpoint the “crossover” date of the proliferation of disease-prone mosquitoes to in six out of seven summers from 2002 to 2008 finding a range of July 25 to August 20. Another model’s pinpoint date was within two weeks of the actual date.

An example of Westcott’s mosquito crossover model from the 2005 season using historical climate percentiles and gradually tending toward a single crossover date as the timing of the 81°F+ day threshold becomes more certain. Image reproduced from Westcott, et. al.

One of the main correlations the past data indicated was that mosquito proliferation coincides quite well with the running total of summer days with high temperatures greater than or equal to 81°F. Once a certain number of days with temperatures at this level had been reached, mosquito proliferation usually occurred within a week. The model used guidance from past climate data to hone in on a date when this threshold was historically reached, replacing this data with actual dates from each individual year as 81°F+ days were logged.

By knowing the crossover date with greater and greater accuracy as the season wears on, the state now prepares the resources to spray exactly when the model indicates the crossover will occur. This more accurate method will save time, money and resources.

While there are other factors that Westcott and her team describe to also have some effect on the model-calculated crossover date (including season precipitation and departure from average daily temperature), they assert that these contribute a comparatively small amount of error to the larger high-temperature correlation. The model will continue to improve every year as each successive summer is modeled and retroactively evaluated to see how it performs and to determine what needs to be tweaked.

Sources

Northwest Mosquito Abatement District. Northwest Mosquito Abatement District, 29 Dec. 2011. Web.  Accessed 18 Jan. 2012.

Westcott, N. E. et al. “Predicting the Seasonal Shift in Mosquito Populations Preceding the Onset of the West Nile Virus in Central Illinois.” Bulletin of the American Meteorological Society. Sep. 2011: 1173-1180. Print.

An example map of anomalies in global precipitation during the MCA. Red ovals indicate drier conditions; blue ovals indicate wetter conditions; and hatched ovals indicate greater uncertainty in the paleorecords. Image reproduced from Diaz et al.

Since the Industrial Revolution in the 18^th and 19^th centuries, carbon dioxide in the atmosphere from the burning of fossil fuels has increased from 280ppm (parts per million) to 390ppm across the globe. This has led to a net warming in the atmosphere to a magnitude that is still being quantified. Complicating the quantification, however is the difficulty of separating natural cycles in the Earth’s orbit (Milankovitch cycles) from human-induced changes in greenhouse gas emissions.

The last time the Earth was entering into a similar warm period due to natural changes in the Earth’s orbit was during medieval times, around 950 AD. This warmer period, dubbed the Medieval Climate Anomaly, or MCA, persisted until approximately 1400 AD. The Earth then slowly started shifting into what is now called the Little Ice Age, which lasted from 1400 to 1900 AD. These eras are confirmed by paleoclimatic records, including ice cores, tree rings and sedimentary analysis. Actual data from weather instruments also substantiate the last few centuries of the Little Ice Age.

Since the beginning of the 20^th century, a steady warming has been well-documented by human observational data and ongoing paleoclimatic research. This warming has also been successfully reproduced in retrospective climate models given the known increase in carbon dioxide concentration in the atmosphere.

Thus, as we prepare for the effects of a slightly warmer climate, we look to the past to see how the Earth adapted to the most recent similarly-warmer period, the MCA. Paleorecords from high- and mid-latitudes in the Northern Hemisphere indicate that temperatures were, for several decades, just as warm as during the 20^th century. Ice data show that sea ice recession in many areas was just as intense as it has been recently. However, some geological records show no noticeable signals of a warm phase.

It can, therefore, be hypothesized that the MCA was stronger in some areas than in others; modifying each region’s climate in different ways. One would expect today’s global warming to behave in a similarly non-uniform manner. This non-uniformity includes differences in magnitude of change and differences in geographic location. This latter difference is one that is often forgotten when discussing changes in the Earth’s climate.

Recent global climate change is not to be a question of ‘if’ but rather of ‘how much.’ Ongoing comparative studies between the MCA and today’s climate will further contribute to a definitive answer to our climate change questions that will not end with determining simply ‘how much’ but will go on to include ‘where.’

Reference:

Diaz, Henry, Ricardo Trigo, Malcolm Hughes, Michael Mann, Elena Xoplaki, and David Barriopedro. “Spatial and Temporal Characteristics of Climate in Medieval Times Revisited.” Bulletin of the American Meteorological Society. Nov. 2011: 1487-1500. Print.

A study performed by the Game and Wildlife Conservation Society concluded that worms can play a key role to help farmers adapt to extreme weather. Worms improve soil structure, reduce water use in the garden, act as natural fertilizers, reduce greenhouse gases and save on the costs of waste removal.

Dr Chris Stoate, head of research at the society’s Allerton Project farm, said:

When fields are not ploughed, the soil condition is improved ­naturally by the tunneling of ­earthworms, which absorb water at a rate of four to 10 times that of fields which are without worm ­tunnels.

This in turn helps the soil to take up water during storms and to retain it during drought.

The study recommended that farmers cut back on traditional ploughing and harness the power of the army of the eco-friendly microbes and earthworms that live in the soil.

Reference

Winter, S. How Turning Worms Will Save Planet (2011, October 11) Express.co.uk. Retrieved from: http://www.express.co.uk/posts/view/274941/How-turning-worms-will-save-planet

Savoie, O. Successful Worm Farming. eHow Retrieved from: http://www.ehow.com/about_5476512_successful-worm-farming.html

by web.missouri.edu

The study of past climate, or paleoclimatology, is one of the most important fields of climate science study. The study of the past, using all time scales, is the basis for climate projections. The past is highly relevant for modern climate change, because it helps us to understand the mechanisms regulating climate and, therefore, to correctly attribute the relative importance of the many factors contributing to climate change, including natural and anthropogenic forces.

The methods for studying the paleoclimate are many and their use depends on the time scale in which researchers are examining. Methods are based on investigating changes in the physical and chemical properties of natural archives, which record climatic patterns.

“Proxy data” is the data paleoclimatologists gather from natural recorders of climate variability. Natural archives can include historical records, tree rings, lake and marine sediments, ice cores, pollen, speleothems, loess and geomorphic features. Natural recorders have different resolutions and can cover different time scales, the shortest being historical data (thousands of years) and the longest marine sediments (millions of years). From these natural archives it is possible to derive past temperature, precipitation and humidity; chemical composition of air and water; as well as vegetation patterns, solar activity, volcanic eruptions, geomagnetic field variations and sea level. A scientist will use all these forms of data to reconstruct the climate of a specific period.

From the study of natural archives, scientists discovered that the ultimate source of natural climate change is Earth’s position with respect to the Sun. Periodic changes in the Earth’s orbit over hundreds of thousands of years gave origin to the ice ages as well as to the inter-glacial eras in between. Climate can change as a result of tectonic movements, as well as to changes in the atmospheric composition, including the concentration of greenhouse gases and dust in the air.

From proxy data networks detailed reconstructions of large-scale temperature patterns over the past millennium have been constructed. These estimates indicate relatively modest variations in Northern Hemisphere mean temperature prior to the marked warming of the twentieth century. This is the footprint of human activity, which started influencing global climate beginning in the Industrial Revolution.

Annually and seasonally resolved climate records are critical to describe year-to-year patterns of climate in past centuries. Spatial resolution of climate data helps to derive a detailed description of global climate patterns. It is key now, in order to understand past and present changes in climate, to assemble the most comprehensive possible data record and to make it accessible for analysis to climatologists all over the world.

References and Further Resources

• NOAA Paleoclimatology located at http://www.ncdc.noaa.gov/paleo/paleo.html
• Gornitz, S. (ed) Encyclopedia of Paleoclimatology and Ancient Environments. Springer.
• Solomon, S., D. et. al. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, (2007) Chapter 6: Paleoclimate. Retrieved at http://ipcc.ch/publications_and_data/ar4/wg1/en/ch6.html.