By Jason Klein

The molecule methane (CH₄) can be found on many planets in our solar system, including Earth. Its presence is essential for life as we know it, and can be found in the guts of cattle and termites. Methane is also a by-product of plant decomposition, and is the major component of natural gas, accounting for about 87% by volume. Thus, methane is just as much a part of our lives as oxygen, carbon, or water.

Methane can be helpful, but it can also be harmful. Not only can methane contribute to the breakdown of the ozone layer (which protects us from harmful solar radiation), but it is also a potent greenhouse gas. In fact, recent research from Liverpool John Moores University suggests that methane produced by dinosaurs may have warmed our planet enough to hasten their downfall – and allowing mammals, including humans, to rise!

Today, one of the most surprising sources of methane is the Arctic Ocean. As the region warms due to climate change and sea ice melts, the water releases significant amounts of the gas, according to a recent study published in the journal Nature Geoscience. In 2009 and 2010, a specially equipped plane was able to detect methane levels roughly equivalent to the eastern Siberian Arctic shelf. Due to the much larger size of the Arctic Ocean, however, scientists would need to adapt their models for future climate change projections. Additionally, as the Earth’s temperature rises, a positive feedback loop is created (more on feedbacks in the climate system coming soon); as more sea ice melts, more methane is discharged, trapping more heat, and so on.

A polar bear on Arctic sea ice. Photo from NASA Earth Observatory.

In 2010, methane levels in the Arctic were measured at a level over twice as high as at any time in the previous 400,000 years. As more methane is released into the atmosphere – from melting Arctic sea ice, tundra, and humanity’s burgeoning appetite for meat – more attention needs to be paid to this important greenhouse gas.

References

Kort, et al. “Atmospheric observations of Arctic Ocean methane emissions up to 82° north.” Nature Geoscience. April, 2012. 318-321.

http://www.telegraph.co.uk/science/dinosaurs/9250032/Dinosaurs-passing-wind-may-have-caused-climate-change.html

FAO (2006). Livestock’s Long Shadow–Environmental Issues and Options. Rome: Food and Agriculture Organization of the United Nations (FAO). http://www.fao.org/docrep/010/a0701e/a0701e00.HTM.

Correlation of carbon dioxide in the atmosphere, seawater, and seawater pH (acidity). Graphic reproduced from Mathaba.

When thinking about climate change, one’s mind often turns to smokestacks, smoggy skies, and the image of mirages on a hot, hazy day. Less considered is what has been called global warming’s “evil twin”: the acidification and warming of the world’s oceans.

In a new research study, marine chemists warn that the present acidification rate of the ocean is well higher than it has been at any time in the last 300 million years. This can be attributed to the ocean absorbing carbon dioxide from the atmosphere. Through this process the ocean has been the most important mitigator of climate change, removing tons of excess carbon from the atmosphere every year.

Like any manmade change to our environment, however, this process is not without consequence. As can be seen in the figure, as atmospheric and seawater carbon dioxide concentrations go up, the average seawater pH continues to decrease, indicating a trend toward increasingly more acidic waters. While a drop in pH of 0.05 may not initially seem like a drastic change, marine scientists assure that this acidification is already affecting delicate marine food webs. One example of this is the 2006-2008 Northwest Oyster Die-off in the US.

Ongoing research into how aquatic life reacts to acidification is similarly not promising. It has been found that in increasingly acidic waters scallop shells corrode, oyster larvae are unable to survive, coral reefs decline, clownfish lose their ability to navigate and sense predators, and the jellyfish population skyrockets.

Estimations from the United Nations indicate that 3 billion people subsidize their diet with fish, and that one billion are directly dependent on fishing as their primary source of food. While ocean acidification may not receive much attention in the global climate change debate, it is obvious that it too needs to be addressed, and addressed soon.

Reference

Mathaba. “Ocean acidity increasing at unprecedented rate.” 28 April 2012, retrieved 6 May 2012. <http://mathaba.net/news/?x=630314>

Photo from NASA

By Luisa Cristini, PhD, University of Hawaii at Manoa.

[Note from the editor: This is the eighth 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.]

Simply stated, climate models are mathematical representations of the climate system, or of parts of it, based on our best knowledge of the natural processes. These representations are expressed by equations. Some climate models can be very complex and require the use of supercomputers to solve the equations.

Many climate models have been developed to perform future climate projections, i.e., to simulate and understand climate changes in response to the emission of greenhouse gases. Models can also be powerful tools to improve our knowledge of the most important characteristics of the climate system and of the causes of climate variations. Climatologists cannot perform experiments on the real climate system to identify the role of a particular process or to test a hypothesis. Therefore, climate models can be used to perform experiments in a virtual world.

For a climate model describing nearly all the components of the system, only a relatively small amount of data is required. This data can include solar irradiance (the amount of solar radiation arriving at a specific spot on the Earth at a specific time), the Earth’s radius and period of rotation, the land topography and bathymetry (the underwater “topography”) of the ocean, some properties of rocks and soils, etc. Data are also important during the development phase of the model, as they provide essential information on the properties of the system that is being modeled. In addition, large numbers of observations are needed to test the validity of the models in order to gain confidence in the conclusions derived from their results.

The models used for future global climate projections are called General Circulation Models (GCMs) and try to account for all of the important properties of the system at the highest affordable resolution. They are divided into Atmospheric General Circulation Models (AGCMs) and Ocean General Circulation Models (OGCMs). For climate studies using interactive atmospheric and oceanic components, the acronyms AOGCM (Atmosphere Ocean General Circulation Model) or CGCM (Coupled General Circulation Model) are generally chosen.

GCMs provide the most precise and complex description of the climate system. They compute the values of model variables at a given time on a horizontal grid across the surface of Earth. These values provide enough information to reconstruct an approximation of the corresponding field over the whole studied area. Currently, the horizontal resolution of GCMs is typically on the order of 100 to 200 km. Also, nowadays, GCMs take more and more components into account, and many new models include sophisticated components for sea ice, carbon cycle, ice sheet dynamics and atmospheric chemistry. Because of the large number of processes included and their relatively high resolution, GCM simulations require a large amount of computer time. For instance, an experiment covering one century typically takes several weeks to run on the fastest computers.

The interactions between the various components of the system (atmosphere, ocean, sea ice, land surface, marine biogeochemistry, and ice sheets) play a crucial role in the dynamics of climate. Some of the interactions are quite straightforward to compute from the model state variables, while more sophisticated parameterizations are required for others.

There is no perfect model suitable for all purposes. This is why a wide range of climate models exist and, depending on the objective or the question, a certain type of model could be selected.  On the other hand, combining the results from various types of models is often the best way to gain a deeper understanding of the dominant processes in action.

Since their invention in the 1950s, GCMs have been further developed and there has been a lot of work and research behind them in each discipline connected to climate science (physics, chemistry, biology, mathematics, geology, and so on). Modern models are very accurate in the representation of the global climate system and are now able to give us insights into both past climate changes and future climate projections.

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.

Trees grow on every continent except Antarctica, and the rings they contain embody a record of climate change going back thousands of years.  Each ring represents a single year’s growth, so not only can a ring count tell us how old a tree is, but they can also help reconstruct climatic history around the world. A giant sequoia might have upward of 3,000 rings, and a bristlecone pine, found in the White Mountains of California, can approach 5,000.

Generally, tree rings’ variations in thickness indicate whether the tree had a good year in terms of favorable temperature and moisture or a bad one. The wood can vary in density from one year to the next as well, again, in response to seasonal weather changes. In regional studies, scientists take more than one sample from a single tree. Most trees are asymmetrical, so scientists can accurately determine the climatic history if samples are taken from several locations in the tree.

A scientist from the University of Arizona bores a tree ring sample for analysis.

Scientists no longer chop down trees to take their samples. Their boring tool drills a small hole in the tree and draws out a cylinder of wood. The cylinders are then glued into grooves, machined into strips, dried, and finally put under a microscope, where the divisions between rings — just one layer of cells thick in some cases — are easily visible. The goal is to find patterns of wider and narrower rings that appear from one tree to the next, along with patterns of density changes. The patterns of rings inform scientists that the tree experienced climatic changes, but doesn’t tell if it was due to variations in temperature or moisture or both. To narrow the probability of error, researchers place modern instruments on trees showing recent changes where the weather is known, and then these changes are compared to historic data collections. Tree samples must be of the same types of trees.

In 2004, the Tree Ring Lab published its North American Drought Atlas, a sample regional study that showed evidence of several megadroughts that parched the continent over the past millennium. Another major study, this time of the Asian Monsoon, suggested that the fall of Angkor, in what is now Cambodia, came partly as a result of megadroughts. Studies are being conducted in Europe to create an Old World Drought Atlas, and tree rings are providing a large portion of the data.

Reference

Lemonick, M.D., (May 3, 2012) “Timelines in Timber: Inside a Tree-Ring Laboratory.” Climate Central retrieved from: http://www.climatecentral.org/news/timelines-in-timber-inside-a-tree-ring-laboratory/

Seventy years of atmospheric data were used in conjunction with financial data from eleven nongovernmental sectors of the US economy: 1) agriculture, 2) communications, 3) construction, 4) manufacturing, 5) mining, 6) retail trade, 7) services, 8.) transportation, 9) utilities, 10) wholesale trade, and 11) finance, insurance, and real estate.

Figure 1: Deer graze near a flooded oil derrick in a field in Louisiana. Image reproduced from AP.

Mining was found to exhibit the greatest economic sensitivity to extreme weather, which makes sense given that oil, coal, and gas extraction is highly sensitive to price fluctuations from consumers due to weather variability. As expected, agriculture was also found to exhibit high economic sensitivity to extreme weather (second only to mining). However, since agriculture makes up less than 1.5% of the US gross domestic product (GDP), its absolute effect is relatively small.

Overall, variation in total precipitation (i.e. floods, droughts) had a larger effect on gross domestic product by state (GSP) than did temperature fluctuations. New York was found to be the most sensitive state, exhibiting an economic sensitivity of up to 13.5% of their GSP during extreme weather events over the course of the seventy years of this study. Tennessee was found to be the least sensitive, with a maximum 2.5% variability in GSP due to extreme weather. As seen in Figure 2, however, no part of the country generally appears to be more economically sensitive than any other part. The authors mention that this was slightly surprising; for example, one might expect coastal Atlantic states to show a slightly higher sensitivity given the recurring impact of tropical storms and hurricanes on those areas.

Figure 2: State economic sensitivity to extreme weather events as a percentage of total GSP. Image reproduced from Lazo et al.

As a whole, the US was shown to have an economic sensitivity of up to just 3.4% of their GDP, a much lower percentage than most of the states on their own. This illustrates the important fact that nationwide economic production can be adaptive in times of extreme weather and temporarily shift to different locales, thereby mitigating a sharp decrease in national production.

Still, of the US GDP ($14.4 trillion at 2008 dollar levels), this 3.4% still accounts for up to $485.2 billion of economic loss due to extreme weather events. The authors of this study suggest that some of the principle ways that some of this loss could be avoided is by investing in production methods such as better insulation of factory roofs, better drainage systems along key transportation routes, and more weather resistant crops.

The continued improvement of forecasting methods will also decrease the US economic sensitivity to extreme weather. However, they also point out that even with perfect forecasts, it is highly unlikely that all sensitivity can be mitigated. Regardless, with $485.2 billion in potential impacts at 2008 levels, the authors assert that it should be obvious this is still no small matter.

Reference

Lazo, J.K., M. Lawson, P. Larsen, and D. Waldman, 2011: U.S. Economic Sensitivity to Weather Variability. Bull. Amer. Meteor. Soc., 92, 709-720.

The British polar research community is at risk. The UK government plans massive cuts, more than 25 percent, to the budget of the British Antarctic Survey (BAS). The cuts are ordered as a means to reduce the UK’s national deficit.

A twilit Antarctic landscape. Reproduced from BAS.

BAS is the leading UK polar research body and one of the world’s most respected polar research institutions.  It was three BAS scientists who discovered the “ozone hole” in the Antarctic in 1974.

Research conducted by the group has encompassed geology, climate change, marine science, and biodiversity, as well as the monitoring of natural hazards, such as sea level rises.

The British Antarctic Survey is a component of the Natural Environment Research Council (NERC). Based in Cambridge, United Kingdom, it has, for over 60 years, undertaken the majority of Britain’s scientific research on and around the Antarctic continent. It now shares that continent with scientists from over thirty countries.

BAS has employed over 400 staff, and supported three stations in the Antarctic at Rothera, Halley and Signy, and two stations on South Georgia, at King Edward Point and Bird Island.

References

F. Andrey (April 9, 2012) “UK Cuts Antarctic Research as More Players Compete for Arctic Resources,” Voice of Russia. Retrieved from: http://english.ruvr.ru/2012_04_09/Antarctic-research-resources/

“British Antarctic Survey,” http://www.antarctica.ac.uk/about_bas/our_organisation/who_we_are.php

The Galápagos Islands off the western coast of South America are renowned as an evolutionary and ecological living laboratory. These Pacific islands can serve as a barometer to gauge how climate and ecosystems interact, and provide a unique window into the relationship between mankind’s rapid development and a continuously changing environment.

The key to understanding how global climate change will likely affect the future of the islands lies in part in understanding the past. Strong El Niño Southern Oscillation (or ENSO) events have greatly shaped the living communities of the islands over millennia, as the archipelago naturally experiences huge regional climate changes.

El Niño represents the greatest natural disturbance to Galápagos ecosystems; without considering anything else, anticipating these natural events is extremely important for biodiversity management. During El Niño events, such as those in 1981/1982 and 1997/ 1998, marine ecosystems starved as upwelling cold water destroyed habitats. Important species that sustained entire communities, such as coral and macroalgae, were devastated. Breeding success for coastal fauna dropped, nesting patterns changed, and a large number of mortalities were observed in birds, reptiles, and sea lions.

On land, species introduced from outside flourished and persisted, and directly threatened native and endemic species better adapted to otherwise arid areas.

Homepage of the Charles Darwin Foundation: www.DarwinFoundation.org

The Charles Darwin Foundation is conducting research to identify the priority vulnerable species and prepare management plans to reduce human-caused threats from fisheries, tourism, and other activities. Scientists expect that the Galápagos penguin, the marine iguana, nesting green turtles, corals, and macroalgaes are particularly susceptible to climate change. Land-based reptiles, adapted to arid conditions and whose reproductive patterns (gender development) depend on nest temperature, will also be studied.

Global climate change could also cause shifts in global resources, markets, and economies that will influence livelihoods of Galápagos inhabitants. Studies will seek to anticipate such impacts on the Galápagos economy in order to help the local population adapt. The project will incorporate scientific research, community outreach, and advice to management authorities to create a long-term monitoring system for the Galápagos, which will enable more informed planning and decision-making.

Time is short if we are to proactively improve how we protect our natural heritage. The Galápagos Islands, being relatively data-rich, have the potential to serve as a barometer for different climate change scenarios, and to begin to answer these immediate pressing questions in order to bring existing information to bear upon the climate change problem.

Reference

Charles Darwin Foundation. “Impact of Climate Variability and Change upon the Galápagos Archipelago”. 26 April 2012. <http://www.darwinfoundation.org/english/pages/interna.php?txtCodiInfo=84>

La Niña has persisted longer than expected this year, and with it comes agricultural uncertainty for many countries across the globe. Rwanda is no exception.

Anthony Twahirwa, head of Rwanda’s Meteorological Center, explains that their forecasting agency expected decreased rainfall as a result of La Niña, or abnormally cool waters in the eastern Pacific, but that they didn’t expect the pattern to persist for as long as it has.

Map of Rwanda. Image reproduced from HistorySpeaks.org.uk

“Normally, the country should have started receiving rains at a regular interval from March this year but we are still waiting for it to start,” explains Twahirwa. With this same pattern happening several years in a row, the problem has been exacerbated and it is expected that the Rwandan government will soon have to start tapping into its emergency food stores.

A big dilemma for Rwandan farmers has been whether or not to plant seeds at all this year. If seeds are not planted, it is certain that there will be no food come harvest time at the end of the summer. Conversely, if seeds are indeed planted, there is a high chance of there not being sufficient moisture for the seeds to germinate this year, and a significant amount of money will have been lost in the planting that could have been avoided. Under either scenario, this year’s harvest will be ruined and the country will have to adopt widespread drought mitigation strategies.

This lack of rainfall comes at a time when temperatures are higher than ever in Rwanda. The last decade was the warmest on record, with 2010 being the hottest year on record. Average maximum temperatures were nearly three degrees warmer between 2001 and 2010 than they were from 1990 to 2000.

Stunted crops in neighboring Tanzania, which has likewise been experiencing record heat and anomalous drought. Image reproduced from Michigan State University.

There are several ways that this scenario could play out in the future. The world could cooperate and find efficient ways to slow global warming by decreasing carbon and methane emissions, preventing further global warming that might contribute to worse droughts. Climate forecasting could get better, which would allow forecasters at Rwanda’s Meteorological Center and across the globe to be prepared for prolonged La Niñas and decreased rains, increasing the chance that farmers, the agricultural sector, and the country’s emergency management service will be better prepared for such a disaster. Or, nothing happens: the world will be unable to agree upon measures to prevent further climate change; accurate climate forecasting will be nearly impossible due to drastic increases in greenhouse gases without precedent; and humanity will plow ever forward toward a potentially disastrous future.

For now, Rwandans will continue to pray for rain, and meteorologists and climatologists will continue to collect weather data to improve forecasts for the region. Forecasts will better empower the peoples of Rwanda to plan for dry times.

References

Agutamba, Kenneth. “Rwanda: Experts Predict Long Droughts, Call to Increase Food Storage.” AllAfrica. 9 April 2012. 23 April 2012.  <http://allafrica.com/stories/201204090542.html>

National Oceanic and Atmospheric Administration. “NOAA’s El Niño Page.” NOAA. 23 April 2012. <http://www.elnino.noaa.gov/>

[Note from the editor: This is the seventh 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 carbon cycle is the biogeochemical cycle by which carbon is exchanged among the different components of the Earth’s system: biosphere, geosphere, hydrosphere, and atmosphere. It is one of the most important cycles of the Earth and allows for carbon to be recycled and reused throughout the Earth’s system.

One of the major changes brought by human activity is the large increase in the atmospheric concentration of carbon dioxide (CO2) and methane (CH4). The concentration of carbon dioxide has increased from around 280 ppm (parts per million) in the year 1800 to over 390 ppm at present [http://www.esrl.noaa.gov/gmd/ccgg/trends/history.html]. CO2 is relatively stable and homogeneous, so that its concentration in the atmosphere is nearly equal away from zones where strong exchanges with the biosphere occur (e.g., over forests).

Methane (CH4) is more reactive than carbon dioxide (CO2) and can be oxidized to form CO2 and water (H2O). Its concentration is lower than that of CO2, but it has increased from 725 ppb (parts per billion) to 1780 ppb in 150 years. Methane is naturally produced by the breakdown of organic matter in lakes and swamps. It is also released into the atmosphere by human activities such as mining, biomass burning, and gas production, as well as the production of rice and by livestock, which produce methane as they digest grass.

The atmosphere is a relatively small reservoir of carbon compared to sedimentary rocks, the ocean and the terrestrial biosphere (which includes non-living organic material such as soil carbon). In particular, more than 50 million gigatons of carbon are stored in the Earth’s crust. This is more than 1,000 times the stock in the ocean, more than 20,000 times the stock in soil, and more than 50,000 times the stock in the atmosphere. However, the changes in the carbon concentration in sedimentary rocks are very small and the associated fluxes are much lower than those between the ocean, the atmosphere, and the soil.

Before the Industrial Era (i.e., before 1750), the exchanges between the various reservoirs were close to equilibrium. However, because of anthropogenic carbon release mainly related to fossil fuel burning and changes in land use (deforestation and agricultural processes), the flux of carbon into the atmosphere has increased dramatically. Up to this point, roughly 45% of the anthropogenic carbon released has remained in the atmosphere, which explains the observed rise in atmospheric CO2. The remaining fraction has been absorbed by the ocean (around 30%) or the terrestrial biosphere (around 25%).

The stability and longevity of CO2 within the atmosphere and ocean will have significant implications on the Earth system, as the resulting radiation imbalance from the enhanced greenhouse effect will alter the global climate for centuries and even millennia to come.

References

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.
NOAA Earth’s System Research Laboratory, Global Monitoring Division (GMD), Carbon Cycle Greenhouse Gases Working Group (CCGG) Carbon cycle toolkit: http://www.esrl.noaa.gov/gmd/outreach/carbon_toolkit/basics.html

Though the Earth is constantly bombarded by charged particles from the Sun, which emits material in all directions in a process known as the solar wind, sometimes the Sun ramps up magnetic activity on its surface, triggering huge flares of insidious plasma.

NASA close-up image of a solar flare (false color).

NASA Science News announced that a huge solar storm occurred between March 8 and 10. “This was the biggest dose of heat we’ve received from a solar storm since 2005,” says Martin Mlynczak of NASA Langley Research Center. The skies at both poles were filled with dramatic aurora displays, also known as the northern and southern lights.

Measured by the SABER sensor onboard the TIMED satellite run by NASA, the sun storm flooded the Earth’s thermosphere, dumping enough energy on Earth to power New York City for two years.  Earth’s gravitational field protected us from most of the storm. The thermosphere re-reradiated 95% of the energy from the storm back into space.

Aurora Borealis (Australis), or the Northern (Southern) Lights, are a visible byproduct of the Earth's magnetosphere repelling energy from the Sun. Image reproduced from CCJ.

While the Earth’s magnetosphere can repel most of the energy from sun storms, there are mounting concerns regarding the Earth’s electrical grid. If they’re powerful enough, geomagnetic storms can temporarily disrupt GPS satellites, radio communications and power grids.

The danger is becoming more critical, as the Sun is approaching what’s known as solar maximum—the high point in our star’s roughly 11-year cycle of activity. Scientists anticipate stronger storms around solar maximum in 2013.

The sprawling electrical grid on Earth’s surface acts like an antenna, allowing currents from the storms to flow into transmission lines. The largest electric currents are funneled toward Earth around the Poles. An example of a power grid being taken down by sun storms includes the transmission system for Canada’s Hydro Quebec in 1989, which left millions of people without power for more than nine hours.

Canadian utilities, being located closer to the magnetic North Pole, actively monitor geomagnetically-induced currents, model impacts for vulnerability, and refine their operational protocols. European utilities and the South African electricity provider, ESKOM, are also preparing for the upcoming solar maximum, in part with advice and data from NASA.

References

Phillips, T. (March 22, 2012) “Solar Storm Dumps Gigawatts into Earth’s Upper Atmosphere,” NASA Science News, Retrieved from: http://science.nasa.gov/science-news/science-at-nasa/2012/22mar_saber/

Jaggard, V. (August 3, 2011) “As Sun Storms Ramp Up, Electric Grid Braces for Impact,” National Geographic Daily News. Retrieved from:  http://news.nationalgeographic.com/news/energy/2011/08/110803-solar-flare-storm-electricity-grid-risk/

Wall, M. (December 29, 2011) “Sun Storms May Slam Earth on Wednesday,” Fox News. Retrieved from: http://www.foxnews.com/scitech/2011/12/28/sun-storms-may-super-charge-northern-lights-wednesday/