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Nồng độ khí quyển các khí gây hiệu ứng nhà kính (GHGs) đang gia tăng như là một kết quả hoạt động của con người (Chương 2 và 4). Xu hướng này bắt đầu với nông nghiệp định cư, và chuyển đổi các hệ sinh thái tự nhiên đất trồng trọt, đồng lúa, và đồng cỏ dẫn đến gia tăng đo lường của khí CO2 và CH4 trong 8000 và 5000 năm qua, | 21 Climate Change and Terrestrial Ecosystem Management Knowledge Gaps and Research Needs I.E. Bauer M.J. Apps J.S. Bhatti and R. Lal CONTENTS 21.1 Introduction.411 21.2 Knowledge Gaps and Research Priorities.413 21.2.1 The Climate System.413 21.2.2 Current Stocks and Fluxes.415 21.2.2.1 C Dynamics of Different Ecosystem Types.415 21.2.2.2 Major Non-CO2 Greenhouse Gases.417 21.2.3 Future Importance of Disturbance.417 21.2.4 Ecosystem Response to Projected Changes.418 21.2.4.1 Agriculture and Forestry.418 21.2.4.2 Wetlands. 420 21.2.5 Strategies Technologies for Adaptation or Mitigation.421 21.2.5.1 Agricultural and Forest Ecosystems.421 21.2.5.2 Wetlands Peatlands.423 21.2.6 Methodological and Interdisciplinary Issues.424 21.3 Conclusion.425 References.426 21.1 INTRODUCTION Atmospheric concentrations of greenhouse gases GHGs are increasing as a result of human activities Chapters 2 and 4 . This trend began with settled agriculture and conversion of natural ecosystems to cropland rice paddies and pasture has resulted in measurable increases of CO2 and CH4 over the past 8000 and 5000 years 411 2006 by Taylor Francis Group LLC 412 Climate Change and Managed Ecosystems respectively.1 With the beginning of the industrial revolution release of CO2 from the burning of fossil fuel has added a new dimension to this phenomenon and rates of change have continually increased through the 19th and 20th centuries. Current atmospheric levels of CO2 are higher than any documented within the past 400 000 years and without effective mitigation are projected to reach twice pre-industrial levels by the end of the 21st century Chapters 2 and 3 . Although it is hard to separate direct effects of climate change from other global change impacts there is mounting evidence that effects of GHG-related warming can already be detected Chapters 3 and 4 . Increases in the frequency of fire in Canadian forests over recent decades for example may be in part attributable to climate warming and there
