Changes in temperature and heat waves over Africa using observational and reanalysis datasets

Aiming to provide comprehensive information for climate change at regional level, we assess temperature and heat waves and their spatiotemporal trend and time of emergence over different regions of the African continent.&#160; We analyze observational data of Climate Research Unit Time Series version 4.03 (CRU TS) and the three state-of-the-art reanalysis datasets; European Center for Medium-Range Weather Forecasts Reanalysis 5 (ERA5), National Oceanic Atmospheric Administration&#8217;s Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA2) and the Japanese Meteorological Agency&#8217;s 55 years reanalysis (JRA-55). We assess changes in monthly mean temperature and the agreement between observations and reanalyses. Changes in heat waves are analyzed based on reanalysis datasets because of their high temporal resolution. Heat waves are defined using absolute and relative thresholds, the number of summer days, tropical nights, the percentage of days with maximum and mean temperature above the 90th percentile, the warm nights and the warm spell duration index. &#160;The results show increasing trends in monthly mean temperature in all four regions of Africa with different rate of change. A statistically significant trends in heat waves is found in all the regions. &#160;Years of highest heat wave occurrence are identified in 2010 for Northern and Western Africa and 2016 for Eastern and Southern Africa. Minimum-temperature based indices, tropical nights and warm nights, show the highest increase in decadal trends and earliest time of emergence, respectively.Key words: climate change; temperature; heat waves; time of emergence; reanalysis; Africa

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Solar geoengineering to limit the rate of temperature change

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2014.0134 ◽

2014 ◽

Vol 372 (2031) ◽

pp. 20140134 ◽

Cited By ~ 48

Author(s):

Douglas G. MacMartin ◽

Ken Caldeira ◽

David W. Keith

Keyword(s):

Climate Change ◽

Climate Model ◽

Rate Of Change ◽

Change Analysis ◽

Rates Of Change ◽

Global Mean Temperature ◽

Mean Temperature ◽

Solar Geoengineering ◽

Allowable Rate ◽

Global Mean

Solar geoengineering has been suggested as a tool that might reduce damage from anthropogenic climate change. Analysis often assumes that geoengineering would be used to maintain a constant global mean temperature. Under this scenario, geoengineering would be required either indefinitely (on societal time scales) or until atmospheric CO 2 concentrations were sufficiently reduced. Impacts of climate change, however, are related to the rate of change as well as its magnitude. We thus describe an alternative scenario in which solar geoengineering is used only to constrain the rate of change of global mean temperature; this leads to a finite deployment period for any emissions pathway that stabilizes global mean temperature. The length of deployment and amount of geoengineering required depends on the emissions pathway and allowable rate of change, e.g. in our simulations, reducing the maximum approximately 0.3°C per decade rate of change in an RCP 4.5 pathway to 0.1°C per decade would require geoengineering for 160 years; under RCP 6.0, the required time nearly doubles. We demonstrate that feedback control can limit rates of change in a climate model. Finally, we note that a decision to terminate use of solar geoengineering does not automatically imply rapid temperature increases: feedback could be used to limit rates of change in a gradual phase-out.

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Contrasting Evolution Patterns of Endorheic and Exorheic Lakes on the Central Tibetan Plateau and Climate Cause Analysis during 1988–2017

Water ◽

10.3390/w13141962 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1962

Author(s):

Zhilong Zhao ◽

Yue Zhang ◽

Zengzeng Hu ◽

Xuanhua Nie

Keyword(s):

Climate Change ◽

Tibetan Plateau ◽

Climatic Factors ◽

Global Climate ◽

Rapid Expansion ◽

Annual Precipitation ◽

The Tibetan Plateau ◽

Lake Area ◽

Climate Change Research ◽

Mean Temperature

The alpine lakes on the Tibetan Plateau (TP) are indicators of climate change. The assessment of lake dynamics on the TP is an important component of global climate change research. With a focus on lakes in the 33° N zone of the central TP, this study investigates the temporal evolution patterns of the lake areas of different types of lakes, i.e., non-glacier-fed endorheic lakes and non-glacier-fed exorheic lakes, during 1988–2017, and examines their relationship with changes in climatic factors. From 1988 to 2017, two endorheic lakes (Lake Yagenco and Lake Zhamcomaqiong) in the study area expanded significantly, i.e., by more than 50%. Over the same period, two exorheic lakes within the study area also exhibited spatio-temporal variability: Lake Gaeencuonama increased by 5.48%, and the change in Lake Zhamuco was not significant. The 2000s was a period of rapid expansion of both the closed lakes (endorheic lakes) and open lakes (exorheic lakes) in the study area. However, the endorheic lakes maintained the increase in lake area after the period of rapid expansion, while the exorheic lakes decreased after significant expansion. During 1988–2017, the annual mean temperature significantly increased at a rate of 0.04 °C/a, while the annual precipitation slightly increased at a rate of 2.23 mm/a. Furthermore, the annual precipitation significantly increased at a rate of 14.28 mm/a during 1995–2008. The results of this study demonstrate that the change in precipitation was responsible for the observed changes in the lake areas of the two exorheic lakes within the study area, while the changes in the lake areas of the two endorheic lakes were more sensitive to the annual mean temperature between 1988 and 2017. Given the importance of lakes to the TP, these are not trivial issues, and we now need accelerated research based on long-term and continuous remote sensing data.

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Poverty and climate change: introduction

Environment and Development Economics ◽

10.1017/s1355770x18000141 ◽

2018 ◽

Vol 23 (3) ◽

pp. 217-233 ◽

Cited By ~ 17

Author(s):

Stephane Hallegatte ◽

Marianne Fay ◽

Edward B. Barbier

Keyword(s):

Climate Change ◽

Agricultural Production ◽

Heat Waves ◽

Future Research ◽

Poor People ◽

Special Issue ◽

National Wealth ◽

Economic Statistics ◽

Climate Vulnerability ◽

Impacts Of Climate Change

AbstractBecause their assets and income represent such a small share of national wealth, the impacts of climate change on poor people, even if dramatic, will be largely invisible in aggregate economic statistics such as the Gross Domestic Product (GDP). Assessing and managing future impacts of climate change on poverty requires different metrics, and specific studies focusing on the vulnerability of poor people. This special issue provides a set of such studies, looking at the exposure and vulnerability of people living in poverty to shocks and stressors that are expected to increase in frequency or intensity due to climate change, such as floods, droughts, heat waves, and impacts on agricultural production and ecosystem services. This introduction summarizes their approach and findings, which support the idea that the link between poverty and climate vulnerability goes both ways: poverty is one major driver of people's vulnerability to climate-related shocks and stressors, and this vulnerability is keeping people in poverty. The paper concludes by identifying priorities for future research.

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Climate Change Trends and Impacts on California Agriculture: A Detailed Review

Agronomy ◽

10.3390/agronomy8030025 ◽

2018 ◽

Vol 8 (3) ◽

pp. 25 ◽

Cited By ~ 42

Author(s):

Tapan Pathak ◽

Mahesh Maskey ◽

Jeffery Dahlberg ◽

Faith Kearns ◽

Khaled Bali ◽

...

Keyword(s):

Climate Change ◽

Agricultural Sector ◽

Climate Adaptation ◽

Crop Yields ◽

Heat Waves ◽

Sufficient Evidence ◽

Future Climate Change ◽

Future Research ◽

Detailed Review ◽

California Agriculture

California is a global leader in the agricultural sector and produces more than 400 types of commodities. The state produces over a third of the country’s vegetables and two-thirds of its fruits and nuts. Despite being highly productive, current and future climate change poses many challenges to the agricultural sector. This paper provides a summary of the current state of knowledge on historical and future trends in climate and their impacts on California agriculture. We present a synthesis of climate change impacts on California agriculture in the context of: (1) historic trends and projected changes in temperature, precipitation, snowpack, heat waves, drought, and flood events; and (2) consequent impacts on crop yields, chill hours, pests and diseases, and agricultural vulnerability to climate risks. Finally, we highlight important findings and directions for future research and implementation. The detailed review presented in this paper provides sufficient evidence that the climate in California has changed significantly and is expected to continue changing in the future, and justifies the urgency and importance of enhancing the adaptive capacity of agriculture and reducing vulnerability to climate change. Since agriculture in California is very diverse and each crop responds to climate differently, climate adaptation research should be locally focused along with effective stakeholder engagement and systematic outreach efforts for effective adoption and implementation. The expected readership of this paper includes local stakeholders, researchers, state and national agencies, and international communities interested in learning about climate change and California’s agriculture.

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The Sensitivity of Persistent Geopotential Anomalies to the Climate of a Moist Channel Model

Journal of Climate ◽

10.1175/jcli-d-20-0254.1 ◽

2021 ◽

pp. 1-52

Author(s):

Gregory Tierney ◽

Walter A. Robinson ◽

Gary Lackmann ◽

Rebecca Miller

Keyword(s):

Climate Change ◽

Heat Release ◽

Latent Heat ◽

Channel Model ◽

Heat Waves ◽

Latent Heat Release ◽

Mean Flow ◽

Flow Variability ◽

Virtual Temperature ◽

Channel Configuration

AbstractHigh-impact events such as heat waves and droughts are often associated with persistent positive geopotential height anomalies (PAs). Understanding how PA activity will change in a future warmer climate is therefore fundamental to projecting associated changes in weather and climate extremes. This is a complex problem because the dynamics of PAs and their associated blocking activity are still poorly understood. Furthermore, climate-change influences on PA activity may be geographically dependent and encompass competing influences. To expose the salient impacts of climate change, we use an oceanic channel configuration of the Weather Research and Forecasting model (WRF) in a bivariate experiment focused on changes in environmental temperature, moisture, and baroclinicity. The 500-hPa wind speed and flow variability are found to increase with increasing temperature and baroclinicity, driven by increases in latent heat release and a stronger virtual temperature gradient. Changes to 500-hPa sinuosity are negligible. PAs are objectively identified at the 500-hPa level using an anomaly threshold method. When using a fixed threshold, PA trends indicate increased activity and strength with warming, but decreased activity and strength with Arctic amplification. Use of a climate-relative threshold hides these trends and highlights the importance of accurate characterization of the mean flow. Changes in PA activity mirror corresponding changes in 500-hPa flow variability and are found to be attributable to changes in three distinct dynamical mechanisms: baroclinic wave activity, virtual temperature effects, and latent heat release.

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Current Threats to the Environmental Conditions in Cities of the Eastern Mediterranean

10.5194/egusphere-egu21-10195 ◽

2021 ◽

Author(s):

Manfred A. Lange

Keyword(s):

Climate Change ◽

Air Quality ◽

Environmental Conditions ◽

Heat Waves ◽

Eastern Mediterranean ◽

Middle Eastern ◽

Liquid Waste ◽

Dust Storms ◽

Urban Structures ◽

Space Cooling

The environmental conditions in urban settings are subject to processes and conditions within cities, on the one hand, and have a strong bearing on the overall conditions and the quality of life of the cities&#8217; inhabitants, on the other. The built environment, in general, and buildings and infrastructure, in particular, play a major role in shaping the urban environment. At the same time, environmental conditions affect strongly the conditions within and outside of buildings.The continued growth of cities in the Eastern Mediterranean and Middle Eastern (EMME) region, the demise of environmental quality adds to the challenges faced by their inhabitants. Of the many factors contributing to these threats, climate change and its amplification in urban structures, the increasing load of pollutants in air and water and the rising numbers of dust storms as well as the growing amount of solid and liquid waste stand out.The significant increase in the number of cars and the rising quantity of energy production has contributed to ever-worsening air quality in EMME cities. More specifically, urban road transport represents one of the major sources of air-borne pollutants in many of these cities and causes substantial threats to the health of their inhabitants.The Middle East and North Africa (MENA) and the EMME region are major sources of desert dust storms that travel north and east to Europe and Asia, thereby strongly affecting cities and their air quality in the EMME. Dust storms and suspended bacteria and viruses pose serious consequences to communities in the EMME region and are likely to worsen due to ongoing climate change.Present and future changes in climate conditions will have numerous adverse effects on the EMME region, in general, and on EMME cities, in particular. This includes extended heat waves as well as enhanced water scarcity for inhabitants and green spaces. In combination with poor air quality, this will cause severe health risks for urban populations as well as the need for increased and extended periods of space cooling in private, commercial and municipal buildings. The greater needs for water and energy in urban structures are interrelated and have been described by the Water-Energy Nexus. The higher demand for water is increasingly satisfied through desalination, which is particularly energy-intensive. The need for additional space cooling during hot spells in cities will require more electricity.The high rate of population growth, ever-increasing urbanization, changes in lifestyles and economic expansion in the EMME countries result in steadily increasing volumes of solid and liquid waste. The waste problems are exacerbated by the rising number of displaced persons and refugees in growing camps in some of the EMME countries, particularly, in Turkey, Jordan and Lebanon. The huge quantity of daily produced sewage sludge in Middle Eastern countries presents a serious challenge due to its high treatment costs and risks to the environment and human health.This paper will address some of these challenges, which call for holistic and interdisciplinary efforts to design effective and sustainable adaptation strategies in EMME cities.

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Rhodoliths in Brazil: Current knowledge and potential impacts of climate change

Brazilian Journal of Oceanography ◽

10.1590/s1679-875920160870064sp2 ◽

2016 ◽

Vol 64 (spe2) ◽

pp. 117-136 ◽

Cited By ~ 26

Author(s):

Paulo Antunes Horta ◽

Pablo Riul ◽

Gilberto M. Amado Filho ◽

Carlos Frederico D. Gurgel ◽

Flávio Berchez ◽

...

Keyword(s):

Climate Change ◽

Global Change ◽

Ocean Acidification ◽

Heat Waves ◽

Current Knowledge ◽

Coastal Pollution ◽

Brazil Current ◽

Run Off ◽

Benthic Ecosystems ◽

Impacts Of Climate Change

Abstract Rhodolith beds are important marine benthic ecosystems, representing oases of high biodiversity among sedimentary seabed environments. They are found frequently and abundantly, acting as major carbonate 'factories' and playing a key role in the biogeochemical cycling of carbonates in the South Atlantic. Rhodoliths are under threat due to global change (mainly related to ocean acidification and global warming) and local stressors, such as fishing and coastal run-off. Here, we review different aspects of the biology of these organisms, highlighting the predicted effects of global change, considering the additional impact of local stressors. Ocean acidification (OA) represents a particular threat that can reduce calcification or even promote the decalcification of these bioengineers, thus increasing the eco-physiological imbalance between calcareous and fleshy algae. OA should be considered, but this together with extreme events such as heat waves and storms, as main stressors of these ecosystems at the present time, will worsen in the future, especially if possible interactions with local stressors like coastal pollution are taken into consideration. Thus, in Brazil there is a serious need for starting monitoring programs and promote innovative experimental infrastructure in order to improve our knowledge of these rich environments, optimize management efforts and enhance the needed conservation initiatives.

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The impact of extreme climatic events on pasture-based dairy systems: a review

Crop and Pasture Science ◽

10.1071/cp16394 ◽

2017 ◽

Vol 68 (12) ◽

pp. 1158 ◽

Cited By ~ 6

Author(s):

J. Chang-Fung-Martel ◽

M. T. Harrison ◽

R. Rawnsley ◽

A. P. Smith ◽

H. Meinke

Keyword(s):

Climate Change ◽

Heat Stress ◽

Heat Waves ◽

Animal Health ◽

Adaptation Strategies ◽

Pasture Production ◽

Potential Productivity ◽

Extreme Climatic Events ◽

Dairy Systems ◽

The Impact

Extreme climatic events such as heat waves, extreme rainfall and prolonged dry periods are a significant challenge to the productivity and profitability of dairy systems. Despite projections of more frequent extreme events, increasing temperatures and reduced precipitation, studies on the impact of these extreme climatic events on pasture-based dairy systems remain uncommon. The Intergovernmental Panel on Climate Change has estimated Australia to be one of the most negatively impacted regions with additional studies estimating Australian production losses of around 16% in the agricultural sector and 9–19% between the present and 2050 in the south-eastern dairy regions of Australia due to climate change. Here we review the literature on the impact of climate change on pasture-based dairy systems with particular focus on extreme climatic events. We provide an insight into current methods for assessing and quantifying heat stress highlighting the impacts on pastures and animals including the associated potential productivity losses and conclude by outlining potential adaptation strategies for improving the resilience of the whole-farm systems to climate change. Adapting milking routines, calving systems and the introduction of heat stress tolerant dairy cow breeds are some proposed strategies. Changes in pasture production would also include alternative pasture species better adapted to climate extremes such as heat waves and prolonged periods of water deficit. In order to develop effective adaptation strategies we also need to focus on issues such as water availability, animal health and associated energy costs.

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