• Journal of Ecology and Environment
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• 제38권1호
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• pp.1-14
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• 2015

Whilst it is clear that increasing temperatures from global environmental change will impact the positions of alpine treelines, it is likely that a range of regional and local scaled factors will mediate the overall impact of global scale climate drivers. We summarized 12 categories of abiotic and biotic factors as 4 groups determining treeline positions. First, there are global factors related to climate-induced growth limitation and carbon limitation. Second, there are seven regional and local factors related to treeline dynamics including frost stress, topography, water stress, snow, wind, fire and non-fire disturbance. Third, species-specific factors can control treeline dynamics through their influence on reproduction and life history traits. Fourth, there are positive feedbacks in structuring the dynamics of treelines. Globally, the commonly accepted growth limitation hypothesis is that growth at a treeline is limited by temperature. Meanwhile, positive feedbacks between canopy cover and tree establishment are likely to control the spatial pattern and temporal dynamics of many treelines. The presence of non-linear dynamics at treelines has implications for the use of treelines as barometers of climate change because the lagged responses and abrupt shifts inherent in non-equilibrium systems may combine to mask the overall climate trend.

• 한국농공학회논문집
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• 제63권4호
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• pp.65-86
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• 2021

This study aims at testing a hypothesis that the resilience of agricultural water systems is characterized by trade-offs and synergies of effects from climate and socioeconomic change. To achieve this, an Agricultural Water System Climate Resilience Assessment (ACRA) framework is established to evaluate comprehensive resilience of an agricultural water system to the combined impacts of the climate and socioeconomic changes with a case study in South Korea. Understanding dynamic behaviors of the agricultural water systems under climate and socioeconomic drivers is not straightforward because the system structure includes complex interactions with multiple feedbacks across components in water and agriculture sectors and climate and socioeconomic factors, which has not been well addressed in the existing decision support models. No consideration of the complex interactions with feedbacks in a decision making process may lead to counterintuitive and untoward evaluation of the coupled impacts of the climate and socioeconomic changes on the system performance. In this regard, the ACRA framework employs a System Dynamics (SD) approach that has been widely used to understand dynamics of the complex systems with the feedback interactions. In the ACRA framework applied to the case study in South Korea, the SD model works along with HOMWRS simulation. The ACRA framework will help to explore resilience-based strategies with infrastructure investment and management options for agricultural water systems.

• 대기
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• 제17권4호
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• pp.483-492
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• 2007

The objective of this study is to describe scientific progresses in understanding of climate change in the Intergovernmental Panel on Climate Change (IPCC) assessment reports, contributed by Working group I. Since 1988, IPCC's four assessment reports showed significant improvements in understanding of observed climate change, drivers of climate change, detection and attribution of climate change, climate models, and future projection. The results are based on large amounts of observation data, sophisticated analyses of data, improvements of climate models and the simulations. While the First Assessment Report (FAR) in 1990 reported that a detectable anthropogenic influence on climate has little observational evidence, the Fourth Assessment Report (AR4) reported that warming of the climate system is unequivocal and is very likely due to human influences. It is also noted that anthropogenic warming and sea level rise would continue for centuries due to the time scales associated with climate processes and feedbacks, even if greenhouse gas were to be stabilized.

• 한국해양학회지:바다
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• 제5권1호
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• pp.10-15
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• 2000

기후변동에 따른 해양생태계의 변화를 예측하기 위한 국제 연구 프로그램인 Global Ocean Ecosystem Dynamics (GLOBEC)은 해양의 탄소순환을 집중적으로 연구한 Joint Global Ocean Flux Study(JGOFS)의 후속조치로서, 이 논문에서는 GLOBEC 프로그램의 목적, 방향, 실천계획, 체제를 정리하였다. 해양과학위원회(SCOR)와 정부간해양위원회(IOC)의 후원을 동시에 받고 있는 대형과학프로그램인 GLOBEC은 기후변화에 따른 생태계의 중위 및 상위포식자의 반응에 대한 연구이며, GLOBEC 과학집행위원회는 연구를 수행하기 위한 실천계획을 1999년에 수립하였다. GLOBEC 프로그램은 국제생지권프로그램(IGBP)의 핵심과제로 지정되어 향후 10년 동안 지속될 것이며, 구체적으로 4개의 연구 초점, 체제구축활동, 지역프로그램, 종합화 등으로 구성되어 있다. 가장 중요한 연구활동인 4개의 연구초점은 다음과 같다: 과거자료분석(Retrospective analyses), 과정 연구(Process studies), 예측과 모델링(Predictive and modelling capability), 되먹임(Feedbacks). 현재, 남극해 GLOBEC(SO-GLOBEC), 소형표층어류와 기후변화(SPACC), 대구와 기후변화(CCC), 기후변화와 환경수용력(CCCC)의 4개 국제적 지역프로그램이 있으며, 이들은 모두 우리나라 해양 및 수산연구와 밀접한 관련이 있다. 미국, 일본 등의 9개국은 국가프로그램을 운영하고 있으며, 이 수효는 점차 증가할 전망이다.

• 농업과학연구
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• 제48권2호
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• pp.311-331
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• 2021

Climate change with extreme hydrological events has become a significant concern for agricultural water systems. Climate change affects not only irrigation availability but also agricultural water requirement. In response, adaptation strategies with soft and hard options have been considered to mitigate the impacts from climate change. However, their implementation has become progressively challenging and complex due to the interconnected impacts of climate change with socio-economic change in agricultural circumstances, and this can generate more uncertainty and complexity in the adaptive management of the agricultural water systems. This study was carried out for the agricultural water supply system in Seongju dam watershed in Seonju-gun, Gyeongbuk in South Korea. The first step is to identify system disturbances. Climate variation and socio-economic components with historical and forecast data were investigated Then, as the second step, problematic trends of the critical performance were identified for the historical and future climate scenarios. As the third step, a system structure was built with a dynamic hypothesis (causal loop diagram) to understand Seongju water system features and interactions with multiple feedbacks across system components in water, agriculture, and socio-economic sectors related to the case study water system. Then, as the fourth step, a mathematical SD (system dynamics) model was developed based on the dynamic hypothesis, including sub-models related to dam reservoir, irrigation channel, irrigation demand, farming income, and labor force, and the fidelity of the SD model to the Seongju water system was checked.

• 한국지구과학회지
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• 제32권2호
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• pp.239-247
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• 2011

국제기후변화협약 및 정부의 저탄소 정책은 기본적으로 과학이 제시한 이산화탄소 증가에 대한 기후민감도에 근거해야 한다. 그러나 기후민감도의 추정치는 현재까지 연구 단위별로 차이가 커서, 이에 대한 과학적 배경, 한계, 전망을 고찰할 필요가 있다. 본 연구에서는 지금까지의 기후민감도에 대한 국내외 연구 결과를 객관적으로 종합하여 검토한다. 기후민감도를 결정하는 것은 대기와 지면의 각종 물리과정에 의한 기후피드백 작용이며, 이 중 특히 태양 단파복사량을 조절하는 구름, 해빙과 관련된 물리과정은 불확실성이 가장 커서, 부정확한 민감도 추정을 야기하는 것으로 보인다. 이 때문에, 최근 인공위성 자료를 이용하여 추정한 기후민감도는 기후모델들이 갖는 범위(대기 중 이산화탄소 2배 증가당 지구평균기온 2-5 K 증가)에 들거나, 그보다 훨씬 작은 값을 갖는다.

• Ocean and Polar Research
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• 제23권4호
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• pp.401-410
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• 2001

Global climate change will alter many such properties of the Southern Ocean as temperature, circulation, stratification, and sea-ice extent. Such changes are likely to influence the species composition and activity of Antarctic marine microorganisms (protists and bacteria) which playa major role in deter-mining the concentration of atmospheric $CO_2$ and producing precursors of cloud condensation nuclei. Direct impacts of climate change on Antarctic marine microorganisms have been determined for very few species. Increasing water temperature would be expected to result in a southward spread of pelagic cyanobacteria, coccolithophorids and others. Growth rates of many species would be expected to increase slightly but nutrient limitation, especially micronutrients, is likely to result in a negligible increase in biomass. The extent of habitats would be reduced for those organisms presently living close to the upper limit of their thermal tolerance. Increased UVB irradiance is likely to favour the growth of those organisms tolerant of UVB and may change the trophic structure of marine communities. Indirect effects, especially those as a consequence of a diminution of the amount of sea-ice and increased upper ocean stratification, are predicted to lead to a change in species composition and impacts on both trophodynamics and vertical carbon flux.

• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.149-157
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• 2019

In this study, we investigate the associations between the solar variability and teleconnection indices, which influence atmospheric circulation and subsequently, the spatial distribution of the global pressure system. A study of the link between the Sun and a large-scale mode of climate variability, which may indirectly affect the Earth's climate and weather, is crucial because the feedbacks of solar variability to an autogenic or internal process should be considered with due care. We have calculated the normalized cross-correlations of the total sunspot area, the total sunspot number, and the solar North-South asymmetry with teleconnection indices. We have found that the Southern Oscillation Index (SOI) index is anti-correlated with both solar activity and the solar North-South asymmetry, with a ~3-year lag. This finding not only agrees with the fact that El $Ni{\tilde{n}}o$ episodes are likely to occur around the solar maximum, but also explains why tropical cyclones occurring in the solar maximum periods and in El $Ni{\tilde{n}}o$ periods appear similar. Conversely, other teleconnection indices, such as the Arctic Oscillation (AO) index, the Antarctic Oscillation (AAO) index, and the Pacific-North American (PNA) index, are weakly or only slightly correlated with solar activity, which emphasizes that response of terrestrial climate and weather to solar variability are local in space. It is also found that correlations between teleconnection indices and solar activity are as good as correlations resulting from the teleconnection indices themselves.

• 한국제4기학회지
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• 제23권1호
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• pp.42-53
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• 2009

최근 급격한 온실가스 증가에 기인하여 대기와 해양 그리고 빙권의 변화가 나타나고 또한 기온과 수분의 함량 변화에 따라서 지표 환경도 서서히 변하기 시작하는 것으로 보고되고 있다. 지표환경의 반응은 생지화학적 반응과 생물리학적 반응으로 구분 할 수 있는데, 생지화학적 반응은 기후변화에 따른 광합성이나 이와 유사한 지표환경의 변화 그리고 이에 따른 화학적인 피드백을 지칭하며 이는 대기의 온실가스 농도를 변화 시키는 역할을 한다. 생물리학적 반응은 기후변화에 따라 식생의 분포가 변하게 되고 이에 따른 태양에너지의 입사율 변화 등과 같은 물리적 반응을 나타낸다. 과거 기후변화역사에도 식생의 변화가 기후변화에 미치는 영향이 매우 컸던 경우가 있었고, 앞으로의 기후변화는 거대하고 급격하게 일어날 것으로 예측되기 때문에, 미래 기후변화의 정확한 예측을 위해서는 지표환경변화의 물리 화학적 변화를 이해하고 예측 모형에 정확히 포함시킬 필요가 있다.

• 한국지구과학회지
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• 제38권7호
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• pp.469-480
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• 2017

Controversy has surrounded the potential impacts of phytoplankton on the tropical climate, since climate models produce diverse behaviors in terms of the equatorial mean state and El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) amplitude. We explored biophysical impacts on the tropical ocean temperature using an ocean general circulation model coupled to a biogeochemistry model in which chlorophyll can modify solar attenuation and in turn feed back to ocean physics. Compared with a control model run excluding biophysical processes, our model with biogeochemistry showed that subsurface chlorophyll concentrations led to an increase in sea surface temperature (particularly in the western Pacific) via horizontal accumulation of heat contents. In the central Pacific, however, a mild cold anomaly appeared, accompanying the strengthened westward currents. The magnitude and skewness of ENSO were also modulated by biophysical feedbacks resulting from the chlorophyll affecting El $Ni{\tilde{n}}o$ and La $Ni{\tilde{n}}a$ in an asymmetric way. That is, El $Ni{\tilde{n}}o$ conditions were intensified by the higher contribution of the second baroclinic mode to sea surface temperature anomalies, whereas La $Ni{\tilde{n}}a$ conditions were slightly weakened by the absorption of shortwave radiation by phytoplankton. In our model experiments, the intensification of El $Ni{\tilde{n}}o$ was more dominant than the dampening of La $Ni{\tilde{n}}a$, resulting in the amplification of ENSO and higher skewness.