Changes in the potential distribution of humid tropical forests on a warmer planet

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 369. N° 1934. Zelazowski Przemyslaw; Malhi Yadvinder; Huntingford Chris; et al. - The Royal Society, 2011

The future of tropical forests has become one of the iconic issues in climate-change science. A number of studies that have explored this subject have tended to focus on the output from one or a few climate models, which work at low spatial resolution, whereas society and conservation-relevant assessment of potential impacts requires a finer scale. This study focuses on the role of climate on the current and future distribution of humid tropical forests (HTFs). We first characterize their contemporary climatological niche using annual rainfall and maximum climatological water stress, which als ...

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Changes in the potential distribution of humid tropical forests on a warmer planet

Przemyslaw Zelazowski ; Yadvinder Malhi ; Chris Huntingford ; Stephen Sitch ; Joshua B. Fisher

in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences > Vol. 369. N° 1934 (2011) . - p. 137-160

The future of tropical forests has become one of the iconic issues in climate-change science. A number of studies that have explored this subject have tended to focus on the output from one or a few climate models, which work at low spatial resolution, whereas society and conservation-relevant assessment of potential impacts requires a finer scale. This study focuses on the role of climate on the current and future distribution of humid tropical forests (HTFs). We first characterize their contemporary climatological niche using annual rainfall and maximum climatological water stress, which also adequately describe the current distribution of other biomes within the tropics. As a first-order approximation of the potential extent of HTFs in future climate regimes defined by global warming of 2°C and 4°C, we investigate changes in the niche through a combination of climate-change anomaly patterns and higher resolution (5 km) maps of current climatology. The climate anomalies are derived using data from 17 coupled Atmosphere–Ocean General Circulation Models (AOGCMs) used in the Fourth Assessment of the Intergovernmental Panel for Climate Change. Our results confirm some risk of forest retreat, especially in eastern Amazonia, Central America and parts of Africa, but also indicate a potential for expansion in other regions, for example around the Congo Basin. The finer spatial scale enabled the depiction of potential resilient and vulnerable zones with practically useful detail. We further refine these estimates by considering the impact of new environmental regimes on plant water demand using the UK Met Office land-surface scheme (of the HadCM3 AOGCM). The CO2-related reduction in plant water demand lowers the risk of die-back and can lead to possible niche expansion in many regions. The analysis presented here focuses primarily on hydrological determinants of HTF extent. We conclude by discussing the role of other factors, notably the physiological effects of higher temperature.

Language(s): English

Format: Digital (Free)

Tags: Climate change ; Climate ; Rainforest ; Global warming ; Scenario ; Tropics Add tag

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Cumulative carbon emissions, emissions floors and short-term rates of warming: implications for policy

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 369. N° 1934. Bowerman Niel H.A.; Frame David J.; Huntingford Chris; et al. - The Royal Society, 2011

A number of recent studies have found a strong link between peak human-induced global warming and cumulative carbon emissions from the start of the industrial revolution, while the link to emissions over shorter periods or in the years 2020 or 2050 is generally weaker. However, cumulative targets appear to conflict with the concept of a ‘floor’ in emissions caused by sectors such as food production. Here, we show that the introduction of emissions floors does not reduce the importance of cumulative emissions, but may make some warming targets unachievable. For pathways that give a most likely ...

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Cumulative carbon emissions, emissions floors and short-term rates of warming: implications for policy

Niel H.A. Bowerman ; David J. Frame ; Chris Huntingford ; Jason A. Lowe ; Myles R. Allen

in Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences > Vol. 369. N° 1934 (2011) . - p. 45-66

A number of recent studies have found a strong link between peak human-induced global warming and cumulative carbon emissions from the start of the industrial revolution, while the link to emissions over shorter periods or in the years 2020 or 2050 is generally weaker. However, cumulative targets appear to conflict with the concept of a ‘floor’ in emissions caused by sectors such as food production. Here, we show that the introduction of emissions floors does not reduce the importance of cumulative emissions, but may make some warming targets unachievable. For pathways that give a most likely warming up to about 4°C, cumulative emissions from pre-industrial times to year 2200 correlate strongly with most likely resultant peak warming regardless of the shape of emissions floors used, providing a more natural long-term policy horizon than 2050 or 2100. The maximum rate of CO2-induced warming, which will affect the feasibility and cost of adapting to climate change, is not determined by cumulative emissions but is tightly aligned with peak rates of emissions. Hence, cumulative carbon emissions to 2200 and peak emission rates could provide a clear and simple framework for CO2 mitigation policy.

Language(s): English

Format: Digital (Free)

Tags: Climate change ; Climate ; Greenhouse gas (GHG) ; Politics ; Greenhouse gas reducing ; Scenario Add tag

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Attribution of Weather and Climate-Related Extreme Events

World Meteorological Organization (WMO) ; Allen Myles R.; Christidis Nikolaos; et al. - WMO, 2011

Unusual or extreme weather and climate-related events are of great public concern and interest, yet there are often conflicting messages from scientists about whether such events can be linked to climate change. There is clear evidence that climate has changed as a result of human-induced greenhouse gas emissions, and that across the globe some aspects of extremes have changed as a result. But this does not imply that the probability of occurrence (or, given a fixed damage, risk) of a specific type of recently observed weather or climate event has changed significantly as a result of human in ...

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 Attribution of Weather and Climate-Related Extreme Events

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World Meteorological Organization (WMO) ; Myles R. Allen ; Nikolaos Christidis ; Randall Dole ; Martin Hoerling ; Chris Huntingford ; Pardeep Pall ; Judith Perlwitz ; Daithi A. Stone

Event: WCRP OSC Climate Research in Service to Society (24-28 October 2011; Sheraton Denver Downtown Hotel, Denver, United States)

Published by: WMO ; 2011

Unusual or extreme weather and climate-related events are of great public concern and interest, yet there are often conflicting messages from scientists about whether such events can be linked to climate change. There is clear evidence that climate has changed as a result of human-induced greenhouse gas emissions, and that across the globe some aspects of extremes have changed as a result. But this does not imply that the probability of occurrence (or, given a fixed damage, risk) of a specific type of recently observed weather or climate event has changed significantly as a result of human influence or that it is likely to become more or less frequent in the future. Conversely, it 2 is sometimes stated that it isn’t possible to attribute any individual weather or climate event to a particular cause. Such statements can be interpreted to mean that human induced climate change could never be shown to be at least partly responsible for any specific event. In this paper we propose a way forward through the development of carefully calibrated physically-based assessments of observed weather and climate-related events and identification of any changed risk of such events attributable to particular factors.

Language(s): English

Format: Digital (Free)

Tags: Natural hazards ; Weather ; Extreme weather event ; Climate change ; Observations ; World Climate Research Programme (WCRP) ; WMO Events' Publications Add tag

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