Climate Change and Forests | Term Paper | Geography

Here is a term paper on ‘Climate Change and Forests’ for class 8, 9, 10, 11 and 12. Find paragraphs, long and short term papers on ‘Climate Change and Forests’ especially written for school and college students.

Term Paper # 1. Introduction to Climate Change:

The apprehension that climate change is one of the greatest challenges currently facing humankind is becoming true day by day. Increased severity and occurrence of natural disasters/changing weather patterns, retreating glaciers, polar ice melt, sea level rise and drought are just some of the consequences already being experienced by populations around the world. Climate change has dual, and sometimes conflicting, implications for forests. Forest ecosystems can act as a tool for mitigation and adaptation to climate change.

Forests remove significant volumes of carbon dioxide from the atmosphere, acting as sinks, capturing carbon and storing it in the forest’s biomass. Forests act as barriers in extreme weather events, preventing topsoil run-off in heavy rains and protecting people, animals and physical infrastructure from the effects of strong winds. However, just as forests have a positive role to play in efforts to combat climate change, forests are also highly vulnerable to changing climate conditions.

The climate at a given location determines the type of forest – boreal, temperate, subtropical or tropical rain forest, that can become established (Figure 6.1). Likewise, when climate conditions change, forests must adapt. However, the time frame required for the adaptation process is usually far longer than the time scale allowed by changing climate conditions.

Forests and woodlands are an important part of our landscape and provide many benefits to society. The tree species that are native to a particular part of the earth have adapted to the local climate, atmosphere and soils over many years. However, human activities have resulted in changes to the natural environment, especially over the last 200 years. As a result of changing climate conditions, forests ability to adapt is compromised resulting in a loss of forest biodiversity and forests themselves, and along with them forests’ ability to adapt to and mitigate the impacts of climate.

Term Paper # 2. Changes in Forest Cover:

All forest types will undergo some changes as a result of altered climate conditions; some of these changes are already occurring but widespread change is expected over the next 50-100 years. In many tropical forests, however, many rainforests may become dry tropical forests with reduced carbon storage capacity.

The diversity in these tropical regions suggests that some form of forest will continue to exist even with severe disturbance, but that many of the functions will change owing to the lack of resilience and new states, in general, will produce considerably less goods and services while supporting less biodiversity than at present.

Most evidence suggest that tropical forests may not be resilient to climate change over the long term, primarily owing to a predicted reduction in rainfall and increased drought. In the short term, evidence suggests a positive effect of CO₂ fertilization on tropical forest production as a result of present climate change, although importantly this has involved some changes in species composition, indicating resilience to current change.

Future capacity of these forests to maintain this service is highly uncertain as a result of altered moisture regimes possibly leading to increased fire and drought. Loss of tropical forests will have consequences for global hydrology, among other consequences of global relevance.

A study was carried out on devastating outbreak of mountain pine beetle in the province of British Columbia, Canada by Konkin and Hopkins (2009). The mountain pine beetle, Dendroctonus ponderosae, is a native bark beetle of the lodge-pole pine (Pinus contorta) forests of western Canada that periodically outbreaks. However, since the late 1990s, populations have grown to an unprecedented scale, now attacking more than 13 million hectares of forest in the province of British Columbia.

The epidemic may be attributed to multiple causes, including climate change and other factors such as forest management interventions. By 2015, the epidemic is expected to kill more than three-quarters of the pine volume in British Columbia representing over 900 million cubic meters of timber that was expected to contribute to the economic wealth of British Columbia’s communities. In these communities climate change is no longer a theoretical matter – the impacts are real now.

This epidemic creates challenges on multiple fronts, but it has also led to new economic opportunities for British Columbia. In addition, it has been a catalyst for increased collaboration among rural communities, natural resource industries and government agencies, and it has fostered new ways of thinking about forest management in the context of climate change and social objectives. Over the past decade, British Columbia has not experienced the extreme cold winter temperatures that curtailed previous outbreaks.

Warming in British Columbia over the twentieth century (to 1995) was approximately equal to the global average of 0.6°C on the coast, but two or three times higher in the interior. The higher winter temperature led to increased winter survival of the mountain pine beetle, which has culminated in the largest beetle epidemic in the province’s recorded history.

From a broader perspective, climate change may lead to a sharp increase in rates of extinction. The study made by Thomas et al. (2004) focusing on five regions of the world suggests that if the climate continues to warm it could dramatically increase the number of species going extinct. Mid-range predictions suggest that 24 per cent of species in these regions will be on their way to extinction by 2050 due to climate change.

This study also indicates that for many species, climate change poses a greater threat to their survival than the destruction of their natural habitat. Other observed impacts of climate change include changes in the timing of reproduction in certain species; in the length of the growing season in many regions; in the abundance of different species; and in the frequency of pest and disease outbreaks.

For example, higher temperatures have led to an increase in the number of eggs laid by the spruce budworm, already one of the most devastating pests in North America’s boreal forest. This could in turn contribute to more severe outbreaks of this pest.

Climate change may also affect species at the level of cells and genes. Changes in the genetic makeup of species are expected as organisms adapt to new climatic conditions, and increases in temperature can also lead to increases in the rate at which cells use energy.

Term Paper # 3. Impact of Climate Change on Indian Forests:

India is a mega-biodiversity country where forests account for about 23.84 per cent (78.37 million ha) of the geographical area. Forests in India are extremely diverse and heterogeneous in nature, and it is difficult to classify them into a small number of categories. The sum total of the pan-Indian ‘miscellaneous forest’ category (with no dominant species) shows the highest (63 per cent) proportion. The miscellaneous forest area occurs under all the forest types.

The other two most dominant forest types are Shorea robusta or sal (12 per cent) in the eastern part of central India and Tectona grandis or teak (9.5 per cent), spread across central India and the Western Ghats in southern India. The increase in precipitation can change the nature of the forest in terms of the floral species dominance, canopy cover, forest dynamics etc.

It can rebuild the connections between fragmented ecosystems, support forest areas to encroach into grasslands, alter tree species dominance and thereby change forest class. On the other hand, reduction in precipitation can support shift towards deciduous category of forests, expansion of grass lands, and lead to forest fragmentation and raise frequencies of forest fire. All these can cause significant change in faunal species distribution, demography and composition.

The main factor that determines the sal or teak domination in the forests of central India is the time of occurrence of rainfall and period of rainfall besides other minor factors. Seeds of sal have a viability of 10 days or so and rains should coincide with this short period of viability.

As the eastern part of the peninsula receives rains from the Bay of Bengal branch of the southwest monsoon, which arrives earlier than the Arabian Sea branch, the germination of sal seeds is favoured and the tree dominates the eastern half of the peninsula; consequently the western counterpart is marked by the dominance of teak.

This example reveals how delicate the link could be between the climate and the geographic distribution of species within a bio-climatic framework as described in the forest classification done by Champion and Seth (1968). The classification states 16 major vegetation types starting from tropical wet evergreen forest to dry alpine forest. The country has largest extent of tropical moist deciduous forest followed by tropical dry deciduous forest. This classification shows that the rainfall pattern influences greatly the forest vegetation pattern though other factors also operate.

Rabindranath et al. (2006) suggested that the predicted increase in the precipitation in the forest areas in the Indian subcontinent is higher than that of the non-forest area. Their study with projected climate models available as 30-year long time series, predicts 2°C to 3.5°C increase in temperature and 250 mm to 500 mm increase in precipitation in the northeastern region.

Increase in rainfall may not have significant impact on the forest areas of northeast which are already experiencing high rainfall but change in temperature regime may cause severe impact and significant changes. Successive reports of IPCC have concluded that even moderate warming and climate change will impact forest ecosystems adversely.

Legris (1963) was one of the first workers to describe possible migration of forest types with a drop of 6°C temperature, as was the case during ice age or with an increase of rainfall during the pluvial phase. Ravindranath et al. (2006) pointed out that global assessments have shown future climate change is likely to significantly affect forest ecosystems. Their study made an assessment of the impact of projected climate change on forest ecosystems in India.

The assessment was based on climate projections of Regional Climate Model of the Hadley Centre (HadRM3) using the A₂ (740 ppm CO₂) and B₂ (575 ppm CO₂) scenarios of Special Report on Emissions Scenarios and the BIOME₄ vegetation response model. Their main conclusion was that under the climate projection for the year 2085, 77 per cent and 68 per cent of the forested grids in India are likely to experience shift in forest types under A₂ and B₂ scenario, respectively.

Indications are a shift towards wetter forest types in the northeastern region and drier forest types in the northwestern region in the absence of human influence. Increasing atmospheric CO₂ concentration and climate warming could also result in a doubling of net primary productivity under the A₂ scenario and nearly 70 per cent increase under the B₂ scenario.

The trends of impacts could be considered as robust but the magnitudes should be viewed with caution, due to the uncertainty in climate projections. Given the projected trends of likely impacts of climate change on forest ecosystems, it is important to incorporate climate change consideration in forest sector long-term planning process.

Bose (2009) apprehends that the Sundarbans, south Asia’s largest carbon sink which mops up carbon dioxide must survive to prevent global warming. Out of 60 varieties of mangrove species that are found in India, Sundarban accounts for 50, many of which are rare. It has a seemingly unlimited capacity to absorb pollutants from air and water.

Though the economic and social benefit arising from this mangrove rehabilitation would be more meaningful to the local communities of this region but it acts as an eye opener to the whole world to understand the concept of forest conservation in mitigating climate change. All constituents of this complex ecosystem depend upon each other.

Any damage to one part will damage and change the whole constitution of the ecology of this area. Sundarban reveals the extreme consequences of climate change and global warming, therefore mangrove plantation is the ultimate solution to this problem.

The state of Gujarat has the largest area of mangrove forests after West Bengal. While the mangroves of the Gulf of Kutch could possibly adapt to low or moderate sea level rise, a rise of more than one meter in the next century could cause serious losses. The mangroves are also threatened by the rise in temperature, which causes decreased tree height and leaf size. Besides sea level rise and temperature stress, the mangroves in the gulf towards Jamnagar and the Kutch coasts are also threatened by drought.

Term Paper # 4. Species Shift and Extinction:

Some important studies have been made on the ecological transformation or more appropriately the process of succession that one may encounter in future. Some studies also suggest that global warming is driving species ranges pole ward and toward higher elevations at temperate latitudes, but evidence for range shifts is scarce for the tropics, where the shallow latitudinal temperature gradient makes upslope shifts more likely than pole ward shifts.

Based on new data for plants and insects on an elevation transect in Costa Rica, the potential for lowland biotic attrition, range-shift gaps, and mountain top extinctions under projected warming were assessed by Colwell et al. (2008). They concluded that tropical lowland biota may face an unparalleled level of net lowland biotic attrition as compared to higher latitudes (where range shifts may be compensated by species from lower latitudes) and that a high proportion of tropical species soon faces gaps between current and projected elevation ranges.

Scientists made a study in Concord, Massachusetts on the phylogenetic patterns of species loss in Thoreau’s woods. During the mid-19^th century, the naturalist and conservationist Henry David Thoreau spent decades exploring the temperate fields, wetlands, and deciduous forests of Concord, Massachusetts, in the northeastern United States. He wrote extensively about the natural history of the area and kept meticulous notes on plant species occurrences and flowering times.

Since then, several botanists have resurveyed the Concord area, thus providing a unique community-level perspective on changes in its floristic composition and flowering times during the past ≈150 years. Despite the fact that 60 per cent of all natural areas in Concord are underdeveloped or have remained well protected, a striking number of species have become locally extinct; 27 per cent of the species documented by Thoreau have been lost, and 36 per cent exist in such low population abundances that their extirpation may be imminent.

Also, the species that have been lost are overly represented in particular plant families, suggesting that extinction risk may be phylogenetically biased. Although habitat loss due to succession and development (e.g., loss of wetlands, abandonment of farms, reforestation, and construction of homes and roads) has contributed to the decrease in abundance for some species in Thoreau’s Concord, climate change may also help to explain the seemingly nonrandom pattern of species loss among certain plant groups.

It has been shown recently that the mean annual temperature in the Concord area has risen by 2.4°C over the past 100 years and that this temperature change is associated with shifts in flowering time. Species are now flowering in an average of 7 days earlier than in Thoreau’s time. Along with changes in flowering phenology, species range is likely to be influenced by climate change. Thus, the Concord surveys provide a unique opportunity to examine the extent to which changes in abundance may be correlated with these climatologically sensitive traits.

Also, by incorporating phylogenetic history into their analyses, they could test whether species that share similar traits were closely related (i.e. phylogenetic conservatism), and to what extent these traits correlated with decreases in abundance. Such findings could identify groups of closely related species that are at higher risk of extinction.

A study of extinction patterns of 25 large mammal species in India finds that improving existing protected areas, creating new areas, and interconnecting them will be necessary for many species to survive this century. They showed that forest cover and local human population densities are also key factors. Fostering greater human cultural tolerance for wildlife likewise will be critical. This study examined extinction probabilities for a range of species.

It looked at species considered endangered or critically endangered in the IUCN Red List of Threatened Speties-2008 (2009), including tigers, lions and elephants and it also looked at species of least concern, including jackals, wolves and other species. Their analysis revealed that protected areas were associated with lower extinction probabilities for 18 species.

Higher proportion of forest cover was associated with lower extinction of seven species. On the other hand, time elapsed since the last historical citing was associated with higher extinction probabilities of 14 species, and human population density in a cell was associated with higher extinction probabilities of 13 species.

To identify factors critical to the species’ survival and estimate their extinction probabilities, the team of researchers collected 30,000 records, including hunting, taxidermy and museum records dating back to 1850. They divided India’s geographical area into a grid with 1,326 individual local “cells” and entered the historical data into each cell. They then used occupancy estimation models, based on observations of more than 100 local wildlife experts, to infer the current occurrence of species in each cell.

One of the most important findings, of the study is that culturally tolerated species (animals that humans perceive as nonthreatening or beneficial) fared better overall. Using both historical data and current occupancy estimation models allowed the researchers to distinguish more clearly between when a species was truly absent or locally extinct in a cell, and when it likely still exists but hasn’t been detected in recent surveys or field observations.

Another study by Cardelus et al. (2006) adds that for conservation to succeed, policymakers and land managers must also take into account rapid changes in land use, climate, population growth and spread, and economic development now occurring in India and southern Asia. To illustrate the potential for elevational range shifts in the tropics, Colwell et al. (2008) analyzed elevational range data for four large survey data sets of plants and insects (epiphytes, under-storey Rubiaceae, geometrid moths, and ants).

The data for all 1902 species were collected by the authors since 2001 from the Barva Transect, a continuously forested corridor ascending2900 m up an elevational gradient from La Selva Biological Station, near sea level, to the top of Volcan Barva, in Costa Rica. In many respects, the predictions illustrated in Figure 6.2 must be considered worst-case scenarios, even if warming occurs as assumed.

Estimating elevational range limits from local inventory data is likely to underestimate regional elevation range, even accounting for local under sampling.

The projections of Colwell et al. (2008) share with species distribution models the assumptions that the fundamental climatic niche of each species is fully expressed by current distributions; that the effects of climate outweigh any idiosyncratic effects of species interactions, dispersal limitation, demographic patterns, or historical contingency; that change will be too rapid for adaptation to warmer temperatures at lower range limits; and that habitats at the landscape scale are homogenous with regard to microclimate.

In fact, species that currently occupy warmer microhabitats at their lower range limit, including lowland species, may shift to currently cooler (and wetter) refuges at the same elevation, in response to warming. The biosphere is not likely to be a purely passive sink for carbon; the changes contributing to the terrestrial carbon sink are likely to be causing profound changes in the ecological balance of ecosystems, with consequences for ecosystem function and species diversity.

Laboratory studies show that responsiveness to high CO₂ varies between species; for example, at the most basic level, the CO₂ response is much higher in plants with a C3 photosynthetic mechanism (all trees, nearly all plants of cold climates, and most temperate crops including wheat and rice) than it is in those with a C4 mechanism (tropical and many temperate grasses, some desert shrubs and some important tropical crops including maize, sorghum and sugar cane).

This has the potential to alter the competitive balance between trees and grasslands. Certain functional groups such as pioneers or lianas may also benefit disproportionately. There have been only a few systematic field studies that have looked for long-term trends in forest composition. For example, in the RAINFOR project, field researchers are re-censusing old- growth forest plots across the Amazon basin to look for evidence of shifts in forest biomass and composition.

Term Paper # 5. Remarks on Climate Change and Forests:

It is a fact that absorbing carbon in trees clearly cannot ‘solve’ the global warming problem on its own as opined by Malhi et al. (2002). However, it is being a significant component in a package of CO₂ mitigation strategies, and providing an immediate carbon sink while other mitigation technologies are developed. Carbon absorbed early in the century has a greater effect on reducing end-of-century temperatures than carbon absorbed late in the century.

Caring for forests in ways that maintain their diversity and resilience is being made even more complex owing to climate change.

Authors like Millar et al. (2007), Schaberg et al. (2008) and Innes et al. (2009) suggested the following as ecological principles that can be employed to maintain and enhance long-term forest resilience, especially under climate change:

1. Maintain genetic diversity in forests through practices that do not select only certain trees for harvesting based on site, growth rate, or form, or practices that depend only on certain genotypes (clones) for planting.

2. Maintain stand and landscape structural complexity using natural forests as models and benchmarks.

3. Maintain connectivity across forest landscapes by reducing fragmentation, recovering lost habitats (forest types), and expanding protected area networks.

4. Maintain functional diversity (and redundancy) and eliminate conversion of diverse natural forests to monotypic or reduced species plantations.

5. Reduce non-natural competition by controlling invasive species and reduce reliance on non-native tree crop species for plantation, afforestation, or reforestation projects.

6. Reduce the possibility of negative outcomes by apportioning some areas of assisted regeneration with trees from regional provenances and from climates of the same region that approximate expected conditions in the future.

7. Maintain biodiversity at all scales (stand, landscape, bioregional) and of all elements (genetic, species, community) and by taking specific actions including protecting isolated or disjunction populations of organisms, populations at margins of their distributions, source habitats and refugia networks. These populations are the most likely to represent pre-adapted gene pools for responding to climate change and could form core populations as conditions change.

8. Ensure that there are national and regional networks of scientifically designed, comprehensive, adequate, and representative protected areas. Build these networks into national and regional planning for large-scale landscape connectivity.