Fire, climate change, carbon and fuel management in the Canadian boreal forest

2001 ◽  
Vol 10 (4) ◽  
pp. 405 ◽  
Author(s):  
B.D. Amiro ◽  
B.J. Stocks ◽  
M.E. Alexander ◽  
M.D. Flannigan ◽  
B.M. Wotton

This paper was presented at the conference ‘Integrating spatial technologies and ecological principles for a new age in fire management’, Boise, Idaho, USA, June 1999 Fire is the dominant stand-renewing disturbance through much of the Canadian boreal forest, with large high-intensity crown fires being common. From 1 to 3 million ha have burned on average during the past 80 years, with 6 years in the past two decades experiencing more than 4 million ha burned. A large-fire database that maps forest fires greater than 200 ha in area in Canada is being developed to catalogue historical fires. However, analyses using a regional climate model suggest that a changing climate caused by increasing greenhouse gases may alter fire weather, contributing to an increased area burned in the future. Direct carbon emissions from fire (combustion) are estimated to average 27 Tg carbon year–1 for 1959–1999 in Canada. Post-fire decomposition may be of a similar magnitude, and the regenerating forest has a different carbon sink strength. Measurements indicate that there is a net carbon release (source) by the forest immediately after the fire before vegetation is re-established. Daytime downward carbon fluxes over a burned forest take 1–3 decades to recover to those of a mature forest, but the annual carbon balance has not yet been measured. There is a potential positive feedback to global climate change, with anthropogenic greenhouse gases stimulating fire activity through weather changes, with fire releasing more carbon while the regenerating forest is a smaller carbon sink. However, changes in fuel type need to be considered in this scenario since fire spreads more slowly through younger deciduous forests. Proactive fuel management is evaluated as a potential mechanism to reduce area burned. However, it is difficult to envisage that such treatments could be employed successfully at the national scale, at least over the next few decades, because of the large scale of treatments required and ecological issues related to forest fragmentation and biodiversity.

2010 ◽  
Vol 19 (8) ◽  
pp. 1127 ◽  
Author(s):  
Yves Bergeron ◽  
Dominic Cyr ◽  
Martin P. Girardin ◽  
Christopher Carcaillet

Natural ecosystems have developed within ranges of conditions that can serve as references for setting conservation targets or assessing the current ecological integrity of managed ecosystems. Because of their climate determinism, forest fires are likely to have consequences that could exacerbate biophysical and socioeconomical vulnerabilities in the context of climate change. We evaluated future trends in fire activity under climate change in the eastern Canadian boreal forest and investigated whether these changes were included in the variability observed during the last 7000 years from sedimentary charcoal records from three lakes. Prediction of future annual area burned was made using simulated Monthly Drought Code data collected from an ensemble of 19 global climate model experiments. The increase in burn rate that is predicted for the end of the 21st century (0.45% year–1 with 95% confidence interval (0.32, 0.59) falls well within the long‐term past variability (0.37 to 0.90% year–1). Although our results suggest that the predicted change in burn rates per se will not move this ecosystem to new conditions, the effects of increasing fire incidence cumulated with current rates of clear‐cutting or other low‐retention types of harvesting, which still prevail in this region, remain preoccupying.


2020 ◽  
Author(s):  
Gulperi Selcan Öncü

<div> <p>In recent times we have often received news such as about melting glaciers, sudden and torrential rain, storms, increased atmospheric temperatures, and forest fires. We have also observed some of these phenomena in our immediate vicinity. There is a frequently used expression among the public, 'the seasons are shifting'. </p> <p>Students have asked the reasons why these changes have been occurring and what about changes between the past and present. In order to understand these changes we all know that they need to understand global warming in the first place. To help them with this as an science teacher I have guided them to be capable of using experimental methods within project-based learning approaches. First they did preliminary literature surveys and then they designed an experiment. In the experiment, they tested the hypothesis that the water inside the bell JAR, which is coated with black cardboard, heats up more than the transparent one. In this way they began to investigate climate change due to greenhouse gases. </p> <p>In the experiment, two bell glasses were used to represent the atmosphere layers. One was intermittently covered with pieces cut out of black cardboard. Black cardboard was used to represent the greenhouse gas due since the black colour absorbs light. Two beakers of the same size were used, filled with water. A thermometer was placed inside and bell jars were turned upside down and put over the beakers. The two thermometers were used to measure the water temperature inside the beakers. </p> <p>The first apparatus is the control group (inside uncovered). The second apparatus is the experimental group (covered with independent black cardboard). In the experimental and observation stage, the independent variable is the bell jar; the dependent variable is the water temperature. The constant variables are the size of the jar, the size of the beaker, the amount of water and the ambient conditions. </p> <p>Having set up the apparatus, the initial temperature of water was measured and recorded. Students carried out the experiment on a sunny day by placing the apparatus in a sun-covered field. They recorded the data in the tables they completed periodically. Then they shared the results with participants at the science festival. </p> <p>In this way they began to investigate the impact of greenhouse gases on climate change.</p> </div>


There is large public and political interest in the predictability of weather and climate, in particular in the influence of human activities on the likely climate change during the next century. Numerical models are the main tools which enable the nonlinear processes involved in the dynamics and physics of the atmosphere and other components of the climate system to be integrated in an effective way. The performance of such models used for weather forecasting has continued to improve as more accurate data with better coverage has become available, as improved descriptions of the physics and dynamics have been incorporated and as computing capacity and speed have increased. Studies of the predictability with models suggest that with further improvements in data and models deterministic forecasting of detailed weather may ultimately have useful skill up to 2-3 weeks ahead. Beyond the limit of deterministic forecasting, some skill remains for the forecasting of general weather patterns which can be pursued by studying ensembles of model forecasts from slightly varying initial conditions. The largest difficulty with further improvements of numerical models lies in their inadequate treatment of the motions too small to be explicitly resolved. Interactions between the atmosphere and the ocean are responsible for substantial variations on seasonal, interannual and longer timescales. Forecasts are being provided of seasonal precipitation in the Sahel region of Africa based on a knowledge of global sea surface tem perature (SST) anomalies together with the assumption that such anomalies tend to persist from one season to the next. Attempts to forecast SST anomalies have centred on tropical regions in particular on the El Nino. Simple models show some skill in forecasting El Nino events 3-9 months in advance. Studies with more elaborate models which as yet only show partial success in simulating these events demonstrate the complex nature of the interactions involved. Turning to the likely changes in climate next century: if no changes occur in the atmosphere other than the increase in C0 2 and other greenhouse gases due to human activities, the increase in radiative forcing due to a doubling of atmospheric C0 2 concentration would lead to an increase of about 1.2 °C in global average temperature. Water vapour and ice-albedo feedbacks raise this to a figure of about 2.5 °C (with an uncertainty range of 1.5—4.5 °C) as estimated by the Intergovernmental Panel for Climate Change. Such a change would dominate over forcing likely to arise from other factors, and this estim ated rate of change next century is probably greater than any which has occurred on earth during the past 10000 years. The main uncertainties in climate change predictions arise from the inadequacies of the models in their descriptions of cloud-radiation and ocean circulation feedbacks. Until there is more confidence in the treatment of these feedbacks there are bound to be large uncertainties associated with any predictions of regional climate change. To reduce the uncertainties there need to be improvements in computer power, in model formulation and in our understanding of climate processes together with a large programme of observations of climate parameters to provide early detection of climate change and to provide validation of climate models and to provide data for initialization of model integrations. An important question is whether changes in climate due to changes in radiative forcing are predictable. It is pointed out that the response to climate over the past half million years to changes in forcing due to the variations in the Earth ’s orbit (Milankovitch cycles) is a regular one; some 60% of variations in the global temperature as established from the palaeontological record occur near frequencies of the Milankovitch cycles. We can, therefore, expect the changes in climate due to increasing greenhouse gases to be a largely predictable response. Large, but probably predictable, changes in the circulation of the deep ocean have modified climate change during past epochs and could have significant influence on future climate change.


Author(s):  
Z. O. Litvintseva ◽  

Forest fires are one of the most important environmental factors affecting the environment. Due to climate change and the increasing frequency of forest fires, studies of the consequences of forest fires and the processes of restoration of disturbed geosystems are relevant. Over the past 20 years, there has been an increase in the frequency of fires on the territory of the Republic of Buryatia as a whole, and the western macro slope of the Barguzin ridge in particular. The situation is aggravated by the fact that a significant part of the fires occur in hardto- reach areas of the ridge, which complicates their elimination. The paper presents the results of observations (2015-2020 years) on the impact of forest fires on the taiga geosystems of the western macroslope of the Barguzin ridge. The features of post-fire restoration of geosystems are considered. The natural restoration of forests depends on the nature of the forest growing conditions and the ecological characteristics of the stands. Restoration of dark coniferous-taiga geosystems, including relict ones, after intense fires has not been revealed, since forest growing conditions are changing. The relevance of the research is also related to the fact that the western macroslope of the Barguzin Ridge is located within the Baikal Natural Territory (BPT), where protected areas are located and it is not uncommon for fires to disrupt relict geosystems that are under protection.


Author(s):  
Robert Mendelsohn

Emissions from greenhouse gases are predicted to cause climate to change. Increased solar radiation gradually warms the oceans, which leads to warmer climates. How much future climates will change depends on the cumulative emissions of greenhouse gases, which in turn depends on the magnitude of future economic growth. The global warming caused by humanmade emissions will likely affect many phenomena across the planet. The future damage from climate change is the net damage that these changes will cause to mankind. Oceans are expected to expand with warmer temperatures, and glaciers and ice sheets are expected to melt, leading to sea level rise over time (a damage). Crops tend to have a hill-shaped relationship with temperature, implying that some farms will be hurt by warming and some farms will gain, depending on their initial temperature. Cooling expenditures are expected to increase (a damage), whereas heating expenditures are expected to fall (a benefit). Water is likely to become scarcer as the demand for water increases with temperature (a damage). Warming is expected to cause ecosystems to migrate poleward. Carbon fertilization is expected to cause forest ecosystems to become more productive, but forest fires are expected to be more frequent so that it is uncertain whether forest biomass will increase or decrease. The expected net effect of all these forest changes is an increase in timber supply (a benefit). It is not known how ecosystem changes will alter overall enjoyment of ecosystems. Warmer summer temperatures will cause health effects from heat waves (a damage), but even larger reductions in health effects from winter cold (a benefit). Large tropical cyclones are expected to get stronger, which will cause more damage from floods and high winds. Winter recreation based on snow will be harmed, but summer outdoor recreation will enjoy a longer season, leading to a net benefit. The net effect of historic climate change over the last century has been beneficial. The beneficial effects of climate change have outweighed the harmful effects across the planet. However, the effects have not been evenly distributed across the planet, with more benefits in the mid to high latitudes and more damage in the low latitudes. The net effect of future climate is expected to turn harmful as benefits will shrink and damages will become more pervasive. A large proportion of the damage from climate change will happen in the low latitudes, where temperatures will be the highest. Measurements of the economic impact of climate change have changed over time. Early studies focused only on the harmful consequences of climate change. Including climate effects that are beneficial has reduced net damage. Early studies assumed no adaptation to climate change. Including adaptation has reduced the net harm from climate change. Catastrophe has been assumed to be a major motivation to do near-term mitigation. However, massive sea level rise, ecosystem collapse, and high climate sensitivity are all slow-moving phenomena that take many centuries to unfold, suggesting a modest present value.


2007 ◽  
Vol 16 (2) ◽  
pp. 153 ◽  
Author(s):  
Cordy Tymstra ◽  
Mike D. Flannigan ◽  
Owen B. Armitage ◽  
Kimberley Logan

Eight years of fire weather data from sixteen representative weather stations within the Boreal Forest Natural Region of Alberta were used to compile reference weather streams for low, moderate, high, very high and extreme Fire Weather Index (FWI) conditions. These reference weather streams were adjusted to create daily weather streams for input into Prometheus – the Canadian Wildland Fire Growth Model. Similar fire weather analyses were completed using Canadian Regional Climate Model (CRCM) output for northern Alberta (174 grid cells) to generate FWI class datasets (temperature, relative humidity, wind speed, Fine Fuel Moisture Code, Duff Moisture Code and Drought Code) for 1 ×, 2 × and 3 × CO2 scenarios. The relative differences between the CRCM scenario outputs were then used to adjust the reference weather streams for northern Alberta. Area burned was calculated for 21 fires, fire weather classes and climate change scenarios. The area burned estimates were weighted based on the historical frequency of area burned by FWI class, and then normalized to derive relative area burned estimates for each climate change scenario. The 2 × and 3 × CO2 scenarios resulted in a relative increase in area burned of 12.9 and 29.4% from the reference 1 × CO2 scenario.


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