A Synthesis of Studies Related to Disturbance Regimes under Global Warming
The words “disturbance” and “global warming” have become part of the wordlist and public discourse. Discussions on global warming often induce fervent responses and stern debate between adherents to different views of the threats or disturbances posed. However, there are many nuances concerning global warming and the threats they represent are not well understood by the society. The society’s understanding rely mostly on images within the popular culture that are often little more than exaggerations of the actual, essential scientific concepts. To appreciate the possible threats and disturbances that global warming represent to planet Earth, it is essential that we first understand the true science underlying these phenomena. The purpose of this report is show the connections between forest disturbance and global warming. At the same time, to assess the implications of these for the welfare of human society, environment, and planet Earth as a whole.
What is a disturbance? According to White & Picket (1985), disturbance is any relatively discrete event in time that disrupts an ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment, including both destructive, catastrophic events as well as less notable, natural environmental fluctuations. Typically, a disturbance causes a significant change in the system under consideration.
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Disturbance “events” are individual disturbances that have a variety of spatial and temporal attributes. Disturbance “regimes”, on the other hand, are the integration of disturbance events over time and space. Disturbance “regimes” can be characterized in terms of area/size, spatial distribution, frequency, and recurrence interval.
Characteristics of Disturbance Regimes
Disturbance regimes can be described in terms of the following ten characteristics: (1) area/size, (2) spatial distribution, (3) frequency, (4) recurrence interval, (5) return interval, (6) rotation period, (7) predictability, (8) magnitude, (9) synergism, and (10) feedbacks.
Area or size is the areal extent of the disturbances, including the size of disturbance patches, the area per event per time period, and the total area per disturbance per time period. Spatial distribution is the spatial distribution of the disturbance, that is, the distribution of events relative to topography, soils, among others. This typically would also impart or reinforce a characteristic spatial scale as well. This would include contagion – the tendency to, and rate of spread, and factors affecting the dispersion of the event. Frequency is the mean number of disturbance events per time period within a specified area. This is probably one of the most commonly reported attributes of a disturbance regime. Recurrence interval is the mean time between disturbance events within a specified area. This is equal to the inverse of the disturbance frequency.
Return interval is the mean time between disturbance events at the same location, that is, how frequently is the same spot of ground disturbed. This is a critical component of the disturbance regime because it directly affects the amount of time the ecosystem, community, or population has to recover before the next disturbance. Rotation period is the mean time to cumulatively disturb an area equivalent to the entire study area. In other words, given the frequency of disturbance events and the area/size disturbed by each event, how long does it take to cumulatively disturb an area equal to the size of the entire study area? Rotation period is equal to the return interval and is thus simply another way to describe the same phenomenon.
Predictability is the variance associated with the recurrence or return interval and/or frequency. If the variance is low, there is high predictability concerning when an area is likely to be disturbed based on the time since last disturbance. If the variance is high, there is a lot of variation in the return interval, making it difficult to predict with any confidence when an area is likely to be disturbed.
Magnitude has two aspects, intensity and severity. Intensity is the magnitude in physical force of the event per unit area and time while severity refers to the magnitude of impact on organism, community, or ecosystem. Synergism refers to the effects of a disturbance event on the occurrence of other disturbances. For example, there may be a synergistic relationship between insect infestations in certain forest types and occurrence of fire. Feedbacks refer to the disturbances that either engender or constrain others. For example, fire may synchronize other subsequent fires in frequency as well as patch boundaries; reciprocally, lack of fire can reinforce a system’s resistance to fire.
Factors Affecting Disturbance Regimes
There are several factors affecting disturbance regimes. Macroclimatic patterns, especially global climate patterns, are often the ultimate regulatory factors in establishing disturbance regimes. Regional and local patterns of topography, soils, and vegetation can also play a critical role in affecting disturbance regimes as well as distribution of people such as roads, trails and communities and human activities such as firewood cutting and camping.
The article “Climate Change and Forest Disturbances” by Dale et al. (2001) is a paper in a series developed by the forest sector of the US National Assessment of the Potential Consequences of Climate Variability and Change. It examines how eight disturbances influence forest structure, composition, and function and how climate change may influence the severity, frequency, and magnitude of disturbances to forests. These eight forest disturbances are the following: (1) fire, (2) drought, (3) insect and pathogen outbreaks, (4) introduced species, (5) hurricanes, (6) windstorms, (7) ice storms, and (8) landslides.
The article focuses on examples in the United States but these disturbances and the effect of climate change take place around the world. Furthermore, it also offers options for managing disturbance under changing climate and discusses research needs that will improve the understanding of how climate change affects forest disturbances.
The frequency, size, intensity, seasonality and types of fires depend on weather, climate, forest structure and composition. Fire initiation and spread depend on the amount and frequency of precipitation, the presence of ignition agents, and conditions such as lightning, fuel availability and distribution, topography, temperature, relative humidity and wind velocity. Effects of fire on forests include acceleration of nutrient cycling, mortality of individual trees, shifts in successional direction, induced seed germination, loss of seed bank, increased landscape heterogeneity, changes in surface-soil organic layers and underground plant root and reproductive tissues, and volatilization of soil nutrients.
Fires also have indirect effects. They affect human health through smoke and also the value of the forest for wildlife habitat, timber and recreation. Fires also cause erosion of soil if soil disturbance accompanies fire such as in fire fighting or timber salvage operations.
Predictions from modeling results suggest huge variation in future fire-weather patterns for the northern portion of North America. For example, seasonal severity rating (SSR) of fire hazard increases over much of North America under the transient general circulation models (GCMs) of the Hadley Center in the United Kingdom (HADCM2SUL) and that of the Canadian Climate Center (CGCM1). Also, according to the Hadley model, a wetter weather in the Northern Great Plains will produce small decreases in SSR and increases will be generally less than 10% over most of the rest of the continent. Furthermore, fire history studies suggest that the frequency of fire can decrease despite warmer temperatures because of increased precipitation. The warmer and drier weather that the CGCM1 model predicts will also produce a 30% increase in SSR for the southeastern United States and Alaska, with about 10% increases elsewhere. The foregoing scenarios suggest an increase in fire intensity and a 25%–50% increase in the area burned in the United States. Furthermore, results from the MC1 model, which is described by Neilson and Drapek (in Dale et al., 2001, p. 726) show an increase in area and biomass burned under both scenarios. This model includes an interaction with CO2 concentrations, which, through increased CO2 fertilization and increased water-use efficiency, produces more biomass and thus more fuel, contributing to more and larger fires under a highly variable climate that has dry years interspersed with wet periods.
The effects of droughts on forest ecosystems are influenced by the following: (1) soil texture and depth, (2) exposure, (3) species present, (4) life stage, and (5) frequency, duration and severity of drought. When a drought occurs a forest responds primarily in the following ways: reduce the net primary production (NPP) and water use, and plants die under severe conditions in which the seedlings and saplings usually are the first to die. Droughts also have secondary effects on forests. Droughts increase susceptibility to insects or disease especially in dense stands. They also reduce decomposition processes, leading to buildup of matter on forest floor that may increase fire frequency or intensity or reduce nutrient cycling.
Climate changes (annual and seasonal) and whether current drought adaptations are sufficient to confer resilience to new conditions determine the consequences of drought (Hanson & Weltzin in Dale et al., 2001, p. 727). A small increase in growing-season temperature could increase evaporative demand, causing moisture stress. According to the models described by Daly et al. (in Dale et al. 2001), namely MAPSS and MC1, this mechanism may cause future increases in drought stress in the Southeast, Southern Rockies, and parts of the Northwest. Furthermore, the Prairie Peninsula and Great Lakes region, parts of the Northwest, and the Gulf Coast could experience drought stress within two decades, even though these regions may become wetter in later decades.
Insect and Pathogen Outbreaks
The survival, reproduction, dispersal and distribution of insects and pathogens are directly influenced by climate. Disturbance from herbivores and pathogens indirectly affects forests in the following ways: elimination of nesting trees for birds, negative effects on mycorrhizal fungi, and impacts on competitors and natural enemies that regulate abundance of potential pests and pathogens. If the intensity and frequency of herbivore and pathogen damage in forests change, it can have a range of effects. The loss of any tree species can significantly reduce overall biodiversity. For example, chestnut blight almost completely eliminated chestnut trees and the die-off of Fraser fir was caused by balsam woolly adelgid. Herbivore and pathogen damage to trees can also increase understory plant diversity, overall abundance and diversity of birds and diversity of predators, parasitoids and detritivores.
Climate change can both directly and indirectly affect herbivores and pathogens through various processes but the ultimate effects on patterns of disturbance include increased disturbance in some areas and decreased disturbance in others. As an example, more northerly outbreaks of southern pine beetles will be favored by an increase in the interannual variation in minimum winter temperatures (Ungerrer et al. in Dale et al., 2001). On the other hand, it will reduce more southerly outbreaks. Similarly, trees’ secondary chemical metabolism and resistance to pests in forests that suffer modest growing-season water deficits will be enhanced by decreased precipitation and increased evapotranspiration. Furthermore, increased warming would most potentially increase the diversity of insects at higher altitudes. Because insects typically migrate much faster than trees, many temperate tree species are likely to encounter nonnative insect herbivores that previously were restricted to subtropical forests.
Global warming has been an international topic of controversy for the past few decades. The definition given by the Oxford Dictionary is, “a gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide and other pollutants.” In National Geographics documentary, Before the Flood, featuring Leonardo DiCaprio, he travels worldwide to places around the country as a United Nations Messenger of Peace to spread awareness about global warming. DiCaprio meets with scientists around the world and goes on expeditions to be able to observe climate change first-handed as well as convening with political figures that oppose the thought of climate change being a real issue. On the journey, DiCaprio also introduces specific interest groups that are trying to undermine the global warming crisis by organizing campaigns that distract the public from the climate issue, therefore he meets with important figures in society to further educate himself and to bring about change in the United States regarding global warming. The documentary suggests ways in which global warming can be monitored and reduced if society takes the necessary measures. This documentary uses an effective approach to send their message about the current situation of climate change and provided solutions in a visual way that appeals to the audience using statistical findings, credible scientists in the field and showing what could happen in the future if global warming is not resolved in a certain time frame.
National Geographic, now mostly known as broadcasting network, is an established magazine company owned by the National Geographic Society founded in 1888. The articles include information relevant to topics of culture, geography and history. National Geographic reports as a highly factual media source that adheres to a strictly pro-science prejudice. To maintain this prejudice, National Geographic only accommodates scientific sources such as legitimate science or an evidence-based source to remain scientifically credible. Legitimate science complies with the scientific method along with continuing to steer clear of bias and loaded words. Additionally, their sources utilize the recognition of professionals’ consensus in the given scientific field as well as exclusively seeking to publish peer reviewed science. Although sources follow scientific principles, few might contain a feeble amount of political bias in particular categories.
Leonardo DiCaprio is a well-known actor who is looking to create a change on a global scale using his critically acclaimed stature in society. Through his foundation called the Leonardo DiCaprio Foundation (LDF), DiCaprio works to better educate society on global warming as well as funding projects to protect ocean and forest environments. Along with these environmentally based projects, he has created numerous documentaries to commence change and increase awareness on the issue. In 2014, during the making of the film, DiCaprio was chosen as a member of the United Nations to be the Messenger of Peace to give a speech focusing on the problem at hand, global warming. Moreover, DiCaprio received an important award called the Crystal Award by the World Economic Forum due to his dedication to his work to globally spread the crucialness of climate change. Not only is he the Chairman of LDF and a United Nations Member, Leonardo also serves on multiple boards of nonprofit organizations like World Wildlife Fund, Natural Resources Defense Council, National Geographic’s Pristine Seas, the funders’ collaborative Oceans 5, and International Fund for Animal Welfare.
Throughout the documentary, important political and science figures are presented and recalled as the most conspectus climate deniers. This cast of experts have been denying all the evidence leaning toward global warming and making money due to their devious ways. Most of these so-called “experts” frequently begin any statements with the phrase “I’m not a climate scientist, but…” before continuing their series of recited talking points that are intended to confuse society on global warming being a problem. These figures are more often than not well-paid operatives by organizations known as The Heartland Institute, CFACT, and Americans for Prosperity. The organizations receive endowments from multiple fossil fuel corporations that are willing to stall any initiative to restrain emissions for fossil fuel or expedite the process of having better energy sources such as solar and wind power to create a more affordable source for society.
As per AR5, which is one of the logical reports at any point attempted, around 9,000 companion assessed research papers put together by researchers from about each nation on the planet, have finished up the ebb and flow discussion of environmental change is finished. One thing it clarified – environmental change is occurring now, and it is now uprooting millions around the world. Floods, superstorms, record-breaking heat, rapidly spreading fires, dry season, strife – due to these sensational changes, some have said we are entering another geologic age. We have left the Holocene and are entering the Anthropocene, an age in which people are the essential drivers of progress on Planet Earth. Our planet is warming up quick, and researchers have demonstrated that the fast changes we are seeing are not because of sun powered action, volcanoes, or other common wonders. They are because of contamination. Around two-thirds of the contamination that is driving environmental change is from the consuming of non-renewable energy sources – coal, oil, and gaseous petrol – with another quarter of the contamination originating from deforestation and farming.
DiCaprio’s effectively uses rhetoric throughout the film to deliver his well worked out message. He conveys his message applying logical, well-organized, and genuine messages as well as applying pathos to appeal to the audiences emotions. For example, the way he uses pathos is appealing to the public’s emotions which informs people about how the planet possibly could be coming to a downfall because of the current climate change that is occuring. Throughout the films entirety, visuals are placed into a slideshow format along with music and incorporates his voice in the background. He integrates many animals and different people in the documentary to receive an emotional response, while using this strategy he guides the audience to maintain focus due to the realization they will soon be affected by climate change. DiCaprio produced the documentary in order to personally touch the spirit of specific individuals, yet the picture was intended to influence the masses. In the documentary DiCaprio interviews many important figures around the world such as the Pope, the President of the United States, Presidents of other well-known countries, doctors, scientist, and other individuals who feel as though climate change is a major issue and that it needs to be addressed.
DiCaprio even addresses the vast carbon impression that he himself has left on the planet, conceding that he here and there inquiries the ethical quality of what he is doing. Though people with no uncertainty will come after this film with blades honed, DiCaprio has the great sense to address these reactions forthright. Also, truly, the creation took endeavors to balance its carbon impression amid shooting, including going up against a willful carbon assess. On the most fundamental level, Before the Flood is a film made for mass utilization with an end goal to educate and goad general society enthusiastically. In that regard, it is successful way of delivering his message. There is a mix of cold hard actualities from master researchers just as exchanges with world pioneers and those straightforwardly affected by the impacts of environmental change. This documentary is available to be seen by any number of individuals as could be expected under the circumstances. Environmental change is real and frightening. Our first line of resistance is in educating the public and keeping in mind that an element film could not in any way, shape or form embody everything there is to know regarding the matter. Before the Flood serves as a not-insignificant piece of education that will optimistically spur people to enact their own further research and hopefully it will provoke action through society. Through this documentary many people will realize that global warming is a world altering issue. This will cause many changes throughout the United States and other nations to lessen global warming, which was what Dicaprio planned on doing by filming Before the Flood.
Global Warming An unnatural weather change is characterized as the relentless increment of the earth’s climate temperature this can be credited to the nursery impact. Although I don’t live in Hollywood, Florida nor have I had the delight of visiting. During my exploration of this for the most part radiant spot, I have arrived at the resolution that the winters are short. Contrasted with Houston as of now and time in Florida the individuals are getting quite bright days. The mugginess when looked at is about the equivalent. People have caused significant atmosphere changes to happen as of now, and we have gotten underway more changes still. Regardless of whether we quit producing ozone-depleting substances today, an Earth-wide temperature boost would keep on occurring for in any event a few additional decades, if not hundreds of years. That is because it takes some time for the planet (for instance, the seas) to react and because carbon dioxide – the dominating warmth catching gas – waits in the climate for many years.
There is a period slack between what we do and when we feel it. Be that as it may, it may not be past the point where it is possible to stay away from or confine a portion of the most exceedingly awful impacts of environmental change. Reusing and driving more eco-friendly vehicles are instances of significant conduct change that will help, yet they won’t be sufficient. Since environmental change is a worldwide, complex issue with financial, social, political and moral repercussions. It’s up to us what occurs, the specific area and the individuals that live there—yet together, the scope of effects makes environmental change one of the direst issues confronting humankind today. Higher temperatures are connected to practically all of the environmental change’s most serious effects, including increasingly visit and extraordinary warmth waves, broad yield disappointments, and emotional moves in creature and plant ranges. The world’s most defenseless individuals—those with least assets and alternatives—will endure the most. As the world warms, ice sheets and icy masses dissolve, and seawater extends. This produces ocean level ascent, which can upset and harm waterfront networks and foundation in basically every ocean flanking nation on the planet.traightaway. In drier zones, a dangerous atmospheric deviation is connected with longer, progressively extraordinary, and increasingly visit dry spells, and a more drawn out fire season.
The immediate effects of environmental change are destroying without anyone else’s input, however, they likewise decline existing disparities and clashes. Creatures, bugs, and plants—effectively undermined by natural surroundings pulverization and contamination—will toll surprisingly more dreadful. Environmental change is one of the most intricate issues confronting us today. It includes numerous measurements – science, financial matters, society, governmental issues, and good and moral inquiries – and is a worldwide issue, felt on nearby scales, that will be around for a considerable length of time and hundreds of years to come. So regardless of whether we quit producing every ozone harming substance today, a worldwide temperature alteration and environmental change will keep on influencing people in the future. Right now, it is ‘submitted’ to some degree of environmental change. The objective is to decrease our weakness on the unsafe impacts of environmental change. It additionally includes capitalizing on any potential valuable open doors related to environmental change. Present-day life is custom-fitted to the steady atmosphere we have gotten acclimated with. As our atmosphere transforms, we should figure out how to adjust. The quicker the atmosphere changes, the harder it could be. While environmental change is a worldwide issue, it is felt on a neighborhood scale. Urban communities and regions are in this manner at the bleeding edge of adjustment. They are attempting to fabricate flood safeguards, plan for heatwaves and higher temperatures, introduce water-porous asphalts to all the more likely arrangement with floods and stormwater and improve water stockpiling and use.