Question

geography

Severe weather describes a sub-type of weather that has particularly notable negative impacts on society. In some cases, whether or not a weather event is severe depends on the geography of where it occurs. Give an example of a weather event that would be considered severe in one place and not severe in another. Please indicate the geographic locations (i.e. Portland, OR) you are comparing. Also, please be climatologically accurate. For example, saying 3 feet of snow is severe in Portland but a normal occurrence in Boston would be incorrect. 3 feet of snow is a lot in any city! Feel free to use the internet to search whether your comparison fits climatology

q2:Human caused global warming is causing the Arctic to warm at a faster rate than the mid-latitudes. Assuming all other conditions are held equal, how would this amplified Arctic warming influence the strength of mid-latitude cyclones? In other words, would they get stronger or weaker or stay the same as a result? Please explain your answer (no credit for getting it correct if there is no explanation)

In most places, when a cold front passes through, the temperature will drop. Why does the temperature in Portland oregon usually not change much after the passage of a cold front?

Answer 1

THE IMPACT OF WEATHER AND CLIMATE ON SOCIETY

There is widespread appreciation for the fact that the value of weather, climate, and environmental data, information, and forecasts is growing in importance to the U.S. economy (e.g., Colgan and Weiher, 2003). According to some estimates, up to 40 percent of the approximately $10 trillion U.S. economy is affected by weather and climate events annually (NRC, 1998a; NOAA, 2001b; Dutton, 2002). The cost of U.S. disasters related to weather and climate is rising rapidly, a consequence of population growth, rising wealth, and social behavior (Changnon, 2000; Pielke and Carbone, 2002). Approximately 90 percent of all presidentially declared disasters in the United States are weather-related (Kelly, 2001). Weather affects aviation, air quality, health, ground and marine transportation, defense, agriculture, fisheries, water, energy, construction, tourism, and many other sectors of the economy. Even “good” weather can cause problems in this complex society; for example, one unexpectedly warm winter day in the Northeast can cost utility companies millions of dollars a day in unused energy.

There is also a growing awareness of the impact of climate variability and change, on time scales ranging from months to decades (NRC, 2001a). Shifts in rainfall patterns associated with climatic variability, such as those accompanying El Niño and La Niña, result in a nation and a world that is often plagued by drought and floods at the same time. Demand for climate data, information, and forecasts is growing rapidly, with NOAA’s National Climate Data Center (NCDC) receiving nearly 2 million online contacts from users in the year 2000, 77 percent from industry.

As society becomes more sensitive to weather, the importance of weather prediction for the protection of lives and property and continued economic growth increases. For example, the U.S. population that resides within 50 miles of the nation’s coastlines and is most threatened by hurricanes and flooding is growing rapidly. Such population growth in these and other high-risk areas significantly increases the need for improved weather predictions and warnings to minimize risks to life and property. Another consideration is that the new economic concept of “just-in-time manufacturing” uses computer-timed and -directed supply systems to eliminate the warehousing of parts and products at ports and factories. However, even minor weather disruptions of land, sea, and air-supply-system pathways caused by snow, ice, and high-wind weather systems can now have large, leveraged impacts on these production systems, whereas previously they had little effect.

According to IPCC (2011) estimates of annual losses have ranged since 1980 from a few billion to above US$200 billion (in 2010 dollars), with the highest value for 2005 (the year of Hurricane Katrina). The global weather-related disaster losses, such as loss of human lives, cultural heritage, and ecosystem services, are difficult to value and monetize, and thus they are poorly reflected in estimates of losses. Yet, recent abnormally intense storms, hurricanes, floods, heatwaves, droughts and associated large-scale wildfires have led to unprecendente negative ecological consequences for tropical forests and coral reefs around the world.

Extreme temperatures

Heat waves

     

2003 European heat wave

Heat waves are periods of abnormally high temperatures and heat index. Definitions of a heatwave vary because of the variation of temperatures in different geographic locations. Excessive heat is often accompanied by high levels of humidity, but can also be catastrophically dry.

Because heat waves are not visible as other forms of severe weather are, like hurricanes, tornadoes, and thunderstorms, they are one of the less known forms of extreme weather. Severe heat weather can damage populations and crops due to potential dehydration or hyperthermia, heat cramps, heat expansion and heat stroke. Dried soils are more susceptible to erosion, decreasing lands available for agriculture. Outbreaks of wildfires can increase in frequency as dry vegetation has increased likeliness of igniting. The evaporation of bodies of water can be devastating to marine populations, decreasing the size of the habitats available as well as the amount of nutrition present within the waters. Livestock and other animal populations may decline as well.

During excessive heat plants shut their leaf pores (stomata), a protective mechanism to conserve water but also curtails plants' absorption capabilities. This leaves more pollution and ozone in the air, which leads to higher mortality in the population. It has been estimated that extra pollution during the hot summer 2006 in the UK, cost 460 lives.The European heat waves from summer 2003 are estimated to have caused 30,000 excess deaths, due to heat stress and air pollution.Over 200 U.S cities have registered new record high temperatures. The worst heatwave in the USA occurred in 1936 and killed more than 5000 people directly. The worst heat wave in Australia occurred in 1938–39 and killed 438. The second worst was in 1896.

Power outages can also occur within areas experiencing heat waves due to the increased demand for electricity (i.e. air conditioning use). The urban heat island effect can increase temperatures, particularly overnight.

Cold waves

  

Cold wave in continental North America from Dec-03 to Dec-10, 2013. Red color means above mean temperature; blue represents below normal temperature.

A cold wave is a weather phenomenon that is distinguished by a cooling of the air. Specifically, as used by the U.S. National Weather Service, a cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to agriculture, industry, commerce, and social activities. The precise criterion for a cold wave is determined by the rate at which the temperature falls, and the minimum to which it falls. This minimum temperature is dependent on the geographical region and time of year. Cold waves generally are capable of occurring any geological location and are formed by large cool air masses that accumulate over certain regions, caused by movements of air streams.

A cold wave can cause death and injury to livestock and wildlife. Exposure to cold mandates greater caloric intake for all animals, including humans, and if a cold wave is accompanied by heavy and persistent snow, grazing animals may be unable to reach necessary food and water, and die of hypothermia or starvation. Cold waves often necessitate the purchase of fodder for livestock at considerable cost to farmers. Human populations can be inflicted with frostbites when exposed for extended periods of time to cold and may result in the loss of limbs or damage to internal organs.

Extreme winter cold often causes poorly insulated water pipes to freeze. Even some poorly protected indoor plumbing may rupture as frozen water expands within them, causing property damage. Fires, paradoxically, become more hazardous during extreme cold. Water mains may break and water supplies may become unreliable, making firefighting more difficult.

Cold waves that bring unexpected freezes and frosts during the growing season in mid-latitude zones can kill plants during the early and most vulnerable stages of growth. This results in crop failure as plants are killed before they can be harvested economically. Such cold waves have caused famines. Cold waves can also cause soil particles to harden and freeze, making it harder for plants and vegetation to grow within these areas. One extreme was the so-called Year Without a Summer of 1816, one of several years during the 1810s in which numerous crops failed during freakish summer cold snaps after volcanic eruptions reduced incoming sunlight.

Global warming

In general, climate models show that with climate change, the planet will experience more extreme weather. In particular temperature record highs outpace record lows and some types of extreme weather such as extreme heat, intense precipitation, and drought have become more frequent and severe in recent decades. Some studies assert a connection between rapidly warming arctic temperatures and thus a vanishing cryosphere to extreme weather in mid-latitudes.

Heat stress

In the PNAS, Steven C. Sherwood and Matthew Huber state that humans and other mammals cannot tolerate a wet-bulb temperature of over 35 °C for extended periods, and that this "would begin to occur with global-mean warming of about 7 °C ... With 11–12 °C warming, such regions would spread to encompass the majority of the human population as currently distributed. Eventual warmings of 12 °C are possible from fossil fuel burning."

Tropical cyclones

  

NASA film In Katrina's Wake, covering the impacts from Hurricane Katrina.

There has been long ongoing debate about a possible increase of tropical cyclones as an effect of global warming.However, the 2012 IPCC special report on extreme events SREX states that "there is low confidence in any observed long-term (i.e., 40 years or more) increases in tropical cyclone activity (i.e., intensity, frequency, duration), after accounting for past changes in observing capabilities."  Increases in population densities increase the number of people affected and damage caused by an event of given severity. The World Meteorological Organization and the U.S. Environmental Protection Agency have in the past linked increasing extreme weather events to global warming, as have Hoyos et al. (2006), writing that the increasing number of category 4 and 5 hurricanes is directly linked to increasing temperatures. Similarly, Kerry Emanuel in Nature writes that hurricane power dissipation is highly correlated with temperature, reflecting global warming.

Hurricane modeling has produced similar results, finding that hurricanes, simulated under warmer, high CO₂ conditions, are more intense than under present-day conditions. Thomas Knutson and Robert E. Tuleya of the NOAA stated in 2004 that warming-induced by greenhouse gas may lead to the increasing occurrence of highly destructive category-5 storms. Vecchi and Soden find that wind shear, the increase of which acts to inhibit tropical cyclones, also changes in model-projections of global warming. There are projected increases of wind shear in the tropical Atlantic and East Pacific associated with the deceleration of the Walker circulation, as well as decreases of wind shear in the western and central Pacific.The study does not make claims about the net effect on Atlantic and East Pacific hurricanes of the warming and moistening atmospheres, and the model-projected increases in Atlantic wind shear.

b)

“There is a real possibility that we will be entering a phase of accelerated Arctic warming in the next two to four decades if mitigation action isn’t taken soon,” says Post, a climate change ecologist at the University of California, Davis.

Post is lead author of the report published today in Science Advances, in which an international group of scientists looks at current and future impacts of polar warming across a range of disciplines.

The Arctic is warming far more quickly than anywhere else on the planet. Temperatures climbed nearly 1.8 degrees Fahrenheit (1 Celsius) in the past decade alone. At the current rate of greenhouse gas emissions, the North is on track to warm 7.2 F (4 C) year-round—and top 12.6 F (7 C) in autumns—by the middle of this century, according to the report. That’s about when the planet as a whole is projected to reach the 3.6 F (2 C) warming often cited as the threshold for disastrous impacts.

Already, the High North is seeing unprecedented changes, including drastic ice losses on land and sea, galloping permafrost thaw, raging wildfires, unseasonal storms, earlier springs, and more. Summer sea ice this year shrank to its second lowest extent since satellite measurements began in 1979, while record July heat melted billions of tons of ice off the Greenland ice sheet. Wildfires blazed across millions of acres from Alaska to Siberia.

“Consequences of recent Arctic warming have already been widespread and pronounced, and yet we haven’t even seen what’s expected to be the most rapid phase of warming,” Post says.

While both the Arctic and Antarctic are experiencing rising temperatures, thinning glaciers, disturbed ecosystems, and other alarming shifts as heat-trapping fossil fuel emissions build up, changes are sweeping the northern region far faster. The impacts of a warming Arctic will be felt well beyond the high latitudes in the near future, the report warns.

Cold fronts are bodies of air with cooler temperatures than the surrounding air, and they normally move from northwest to southeast. The temperature shift between cold and warm fronts can be drastic, from freezing temperatures near the cold front to warm temperatures close to the warm front. On a weather map, cold fronts are shown as curved blue lines with triangles pointing in the direction that the front is moving.