نتایج جستجو برای: climate changes

تعداد نتایج: 1011976  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
J R Marlon P J Bartlein M K Walsh S P Harrison K J Brown M E Edwards P E Higuera M J Power R S Anderson C Briles A Brunelle C Carcaillet M Daniels F S Hu M Lavoie C Long T Minckley P J H Richard A C Scott D S Shafer W Tinner C E Umbanhowar C Whitlock

It is widely accepted, based on data from the last few decades and on model simulations, that anthropogenic climate change will cause increased fire activity. However, less attention has been paid to the relationship between abrupt climate changes and heightened fire activity in the paleorecord. We use 35 charcoal and pollen records to assess how fire regimes in North America changed during the...

2006
R. J. Stouffer A. J. Pitman

First, we review the evidence that abrupt climate changes have occurred in the past and then demonstrate that climate models have developing capacity to simulate many of these changes. In particular, the processes by which changes in the ocean circulation drive abrupt changes appear to be captured by climate models to a degree that is encouraging. The evidence that past changes in the ocean hav...

The climate changes have an important role in distribution of plant species. Statistical species distribution models (SDMs) are widely used to predict the changes in species distribution under climate change scenarios. In the peresent study, the distribution of Alopecurus textilis in the current and future climate condition (2050) under the influence of climate change and two scenarios of RCP 4...

Journal: :محیط زیست طبیعی 0
سیده شعله حسینی کارشناس ارشد محیط زیست، دانشگاه آزاد، واحد علوم و تحقیقات حمید رضا غفارزاده عضو هیئت علمی دانشکده محیط زیست و انرژی، دانشگاه آزاد واحد علوم و تحقیقات زهرا عابدی عضو هیئت علمی دانشکدة محیط زیست و انرژی، دانشگاه آزاد واحد علوم و تحقیقات نیما شیری پردیس علوم کشاورزی و منابع طبیعی، دانشگاه تهران

the objective of this study is to investigate of climate change in gorgan river-gharesoo basin and these impacts of this phenomenon on regional land use change, as well as provide guidance on the effective management and conservation of natural land area. analysis of climate data including rainfall, average temperature and relative humidity of nine synoptic stations in this area from east to we...

Abbas ali Tayefi Nasrabadi Atefeh Dehghan Touranposhti

A new challenge which the world will face in near future is the reduction of water resources regarding to global climate changes. Climate change is one of the phenomena which will threats future of the universe. Iran locates in an arid and semi-arid region and has limited water resources. Based on global and Intergovernmental Panel on Climate Change (IPCC) board database and the statistics of s...

ژورنال: آبخیزداری ایران 2019

Any changes in the climate system affect on the access and management of natural resources such as water and soil. Temperature and precipitation are the key elements of climate for studying their trend can be important for atmospheric scientists, environmental managers and planners in the field of hydrology, agriculture, environment and so on. In this study, the trend of climate fluctuations wa...

Journal: :توسعه کارآفرینی 0
محمد رضا اکبری دانشجوی دکتری کشاورزی دانشگاه تهران احمد رضوانفر استاد گروه ترویج و آموزش کشاورزی، دانشکده اقتصاد و توسعه کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران امیر علم بیگی استادیار گروه ترویج و آموزش کشاورزی، دانشکده اقتصاد و توسعه کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران

the agricultural sector was affected by climate change more than every other sectors, because it is close to nature. in other words, the effects of climate change were been on the farmers’ livelihood. farmers need to entrepreneurial changes for adaptation to climate change in their livelihood. hence, investigation of farmers’ entrepreneurial behavior in response to climate change was the main p...

Journal: :Faraday discussions 2005
David Stevenson Ruth Doherty Michael Sanderson Colin Johnson Bill Collins Dick Derwent

Two coupled climate-chemistry model experiments for the period 1990-2030 were conducted: one with a fixed climate and the other with a varying climate forced by the is92a scenario. By comparing results from these experiments we have attempted to identify changes and variations in physical climate that may have important influences upon tropospheric chemical composition. Climate variables consid...

2014
Maggie Hodges Jessica H. Belle Elizabeth J. Carlton Song Liang Huazhong Li Wei Luo Matthew C. Freeman Yang Liu Yang Gao Jeremy J. Hess Justin V. Remais

Despite China's rapid progress improving water, sanitation and hygiene (WSH) access, in 2011, 471 million people lacked access to improved sanitation and 401 million to household piped water. Because certain infectious diseases are sensitive to changes in both climate and WSH conditions, we projected impacts of climate change on WSH-attributable diseases in China in 2020 and 2030 by coupling es...

Journal: :Science 2000
D R Easterling G A Meehl C Parmesan S A Changnon T R Karl L O Mearns

One of the major concerns with a potential change in climate is that an increase in extreme events will occur. Results of observational studies suggest that in many areas that have been analyzed, changes in total precipitation are amplified at the tails, and changes in some temperature extremes have been observed. Model output has been analyzed that shows changes in extreme events for future cl...

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