scholarly journals Trends and patterns in the contributions to cumulative radiative forcing from different regions of the world

2018 ◽  
Vol 115 (52) ◽  
pp. 13192-13197 ◽  
Author(s):  
D. M. Murphy ◽  
A. R. Ravishankara

Different regions of the world have had different historical patterns of emissions of carbon dioxide, other greenhouse gases, and aerosols as well as different land-use changes. One can estimate the net cumulative contribution by each region to the global mean radiative forcing due to past greenhouse gas emissions, aerosol precursors, and carbon dioxide from land-use changes. Several patterns stand out from such calculations. Some regions have had a common historical pattern in which the short-term offsets between the radiative forcings from carbon dioxide and sulfate aerosols temporarily led to near-zero radiative forcing during periods of exponential emissions growth with few emission controls. This happened for North America and Europe in the mid-20th century and China in the 1990s and 2000s. However, these same periods lead to a commitment to future radiative forcing from the carbon dioxide and other greenhouse gases that stay in the atmosphere long after the aerosols. For every region, this commitment to future radiative forcing (2018–2100) from emissions already in the atmosphere is larger than the cumulative radiative forcing to date (1900–2017). This comparison again highlights how the full radiative forcing from greenhouse gases is unmasked once the aerosol emissions are reduced to improve air quality. The relative contributions from various regions to global climate forcing depends more on the time the contributions are compared (e.g., now or 2100) and future development scenarios than on whether cumulative radiative forcing, ocean heat content, or temperature is used to compare regional contributions.

2015 ◽  
Vol 6 (1) ◽  
pp. 175-194 ◽  
Author(s):  
D. S. Ward ◽  
N. M. Mahowald

Abstract. Identifying and quantifying the sources of climate impacts from land use and land cover change (LULCC) is necessary to optimize policies regarding LULCC for climate change mitigation. These climate impacts are typically defined relative to emissions of CO2, or sometimes emissions of other long-lived greenhouse gases. Here we use previously published estimates of the radiative forcing (RF) of LULCC that include the short-lived forcing agents O3 and aerosols, in addition to long-lived greenhouse gases and land albedo change, for six projections of LULCC as a metric for quantifying climate impacts. The LULCC RF is attributed to three categories of LULCC activities: direct modifications to land cover, agriculture, and wildfire response, and sources of the forcing are ascribed to individual grid points for each sector. Results for the year 2010 show substantial positive forcings from the direct modifications and agriculture sectors, particularly from south and southeast Asia, and a smaller magnitude negative forcing response from wildfires. The spatial distribution of future sources of LULCC RF is highly scenario-dependent, but we show that future forest area change can be used as a predictor of the future RF from direct modification activities, especially in the tropics, suggesting that deforestation-prevention policies that value land based on its C-content may be particularly effective at mitigating climate forcing originating in the tropics from this sector. However, the response of wildfire RF to tropical land cover changes is not as easily scalable and yet imposes a non-trivial feedback onto the total LULCC RF.


2014 ◽  
Vol 5 (2) ◽  
pp. 1751-1792
Author(s):  
D. S. Ward ◽  
N. M. Mahowald

Abstract. Identifying and quantifying the sources of climate impacts from land use and land cover change (LULCC) is necessary to optimize policies regarding LULCC for climate change mitigation. These climate impacts are typically defined relative to emissions of CO2, or sometimes emissions of other long-lived greenhouse gases. Here we use previously published estimates of the radiative forcing (RF) of LULCC that include the short-lived forcing agents O3 and aerosols, in addition to long-lived greenhouse gases and land albedo change, for six projections of LULCC as a metric for quantifying climate impacts. The LULCC RF is attributed to three categories of LULCC activities: direct modifications to land cover, agriculture, and wildfire response, and sources of the forcing are ascribed to individual grid points for each sector. Results for the year 2010 show substantial positive forcings from the direct modifications and agriculture sectors, particularly from India, China, and southeast Asia, and a smaller magnitude negative forcing response from wildfires. The RF from direct modifications, mainly deforestation activities, exhibits a large range in future outcomes for the standard future scenarios implying that these activities, and not agricultural emissions (which lead to more consistent RFs between scenarios), will drive the LULCC RF in the future. We show that future forest area change can be used as a predictor of the future RF from direct modification activities, especially in the tropics, suggesting that deforestation-prevention policies that value land based on its C-content may be particularly effective at mitigating climate forcing originating in the tropics from this sector. Although, the response of wildfire RF to tropical land cover changes is not as easily scalable and yet imposes a non-trivial feedback onto the total LULCC RF.


2021 ◽  
Vol 13 (18) ◽  
pp. 10153
Author(s):  
Fang Zhao ◽  
Xincan Lan ◽  
Wuyang Li ◽  
Wenbo Zhu ◽  
Tianqi Li

Land use changes affect the surface radiative budget and energy balance by changing the surface albedo, which generates radiative forcing, impacting the regional and global climate. To estimate the effect of land use changes on the surface albedo and climate change in a mountainous area with complex terrain, we obtained MODIS data, identified the spatial–temporal characteristics of the surface albedo caused by land use changes, and then calculated the radiative forcing based on solar radiative data and the surface albedo in the Qinling-Daba mountains from 2000 to 2015. The correlation between the land use changes and the radiative forcing was analyzed to explore the climate effects caused by land use changes on a kilometer-grid scale in the Qinling-Daba mountains. Our results show that the primarily land use changes were a decrease in the cultivated land area and an increase in the construction land area, as well as other conversions between six land use types from 2000 to 2015. The land use changes led to significant changes in the surface albedo. Meanwhile, the radiative forcing caused by the land use had different magnitudes, strengths, and occurrence ranges, resulting in both warming and cooling climate change effects.


2021 ◽  
Vol 13 (9) ◽  
pp. 4599
Author(s):  
Mohd Alsaleh ◽  
Muhammad Mansur Abdulwakil ◽  
Abdul Samad Abdul-Rahim

Under the current European Union (EU) constitution approved in May 2018, EU countries ought to guarantee that estimated greenhouse-gas releases from land use, land-use change, or forestry are entirely compensated by an equivalent accounted removal of carbon dioxide (CO2) from the air during the period between 2021 and 2030. This study investigates the effect of sustainable hydropower production on land-use change in the European Union (EU28) region countries during 1990–2018, using the fully modified ordinary least squares (FMOLS). The results revealed that land-use change incline with an increase in hydropower energy production. In addition, economic growth, carbon dioxide emissions, and population density are found to be increasing land-use changes, while institutional quality is found to be decreasing land-use change significantly. The finding implies that land-use change in EU28 region countries can be significantly increased by mounting the amount of hydropower energy production to achieve Energy Union aims by 2030. This will finally be spread to combat climate change and environmental pollution. The findings are considered robust as they were checked with DOLS and pooled OLS. The research suggests that the EU28 countries pay attention to the share of hydropower in their renewable energy combination to minimize carbon releases. Politicians and investors in the EU28 region ought to invest further in the efficiency and sustainability of hydropower generation to increase its production and accessibility without further degradation of forest and agricultural conditions. The authorities of the EU28 region should emphasize on efficiency and sustainability of hydropower energy with land-use management to achieve the international commitments for climate, biodiversity, and sustainable development, reduce dependence on fossil fuel, and energy insecurity.


2014 ◽  
Author(s):  
Samuele Del Bianco ◽  
Bruno Carli ◽  
Marco Gai ◽  
Lucia Maria Laurenza ◽  
Ugo Cortesi

Carbon dioxide (CO<sub>2</sub>) is the main greenhouse gas released into the Earth’s atmosphere by human activities. The concentration of CO<sub>2</sub> in the atmosphere depends on the balance of natural sources and sinks, which are being perturbed by anthropogenic forcing due to fossil fuel burning, uncontrolled urban development, deforestation and other land use changes. An improvement in our understanding of processes responsible for absorption of CO<sub>2</sub> is urgently needed both for a reliable estimate of future CO<sub>2</sub> levels, and for the enforcement of effective international agreements for its containment. [...]


2008 ◽  
Vol 8 (2) ◽  
pp. 7373-7389 ◽  
Author(s):  
A. Stohl

Abstract. Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who – like other scientists – rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of carbon dioxide (CO2). In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU) caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc.) were calculated for the years 2005–2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.


Author(s):  
Michael H. Fox

We, the teeming billions of people on earth, are changing the earth’s climate at an unprecedented rate because we are spewing out greenhouse gases and are heading to a disaster, say most climate scientists. Not so, say the skeptics. We are just experiencing normal variations in earth’s climate and we should all take a big breath, settle down, and worry about something else. Which is it? A national debate has raged for the last several decades about whether anthropogenic (man-made) sources of carbon dioxide (CO2 ) and other so-called “greenhouse gases“ (primarily methane and nitrous oxide) are causing the world to heat up. This phenomenon is usually called “global warming,” but it is more appropriate to call it “global climate change,” since it is not simply an increase in global temperatures but rather more complex changes to the overall climate. Al Gore is a prominent spokesman for the theory that humans are causing an increase in greenhouse gases leading to global climate change. His movie and book, An Inconvenient Truth, gave the message widespread awareness and resulted in a Nobel Peace Prize for him in 2008. However, the message also led to widespread criticism. On the one hand are a few scientists and a large segment of the general American public who believe that there is no connection between increased CO2 in the atmosphere and global climate change, or if there is, it is too expensive to do anything about it, anyway. On the other hand is an overwhelming consensus of climate scientists who have produced enormous numbers of research papers demonstrating that increased CO2 is changing the earth’s climate. The scientific consensus is expressed most clearly in the Fourth Assessment Report in 2007 by the United Nations–sponsored Intergovernmental Panel on Climate Change (IPCC), the fourth in a series of reports since 1990. The IPCC began as a group of scientists meeting in Geneva in November 1988 to discuss global climate issues under the auspices of the World Meteorological Organization and the United Nations Environment Program.


2014 ◽  
Vol 14 (19) ◽  
pp. 26297-26348
Author(s):  
S. D. D'Andrea ◽  
J. C. Acosta Navarro ◽  
S. C. Farina ◽  
C. E. Scott ◽  
A. Rap ◽  
...  

Abstract. Emissions of biogenic volatile organic compounds (BVOC) have changed in the past millennium due to changes in land use, temperature and CO2 concentrations. Recent model reconstructions of BVOC emissions over the past millennium predicted changes in dominant secondary organic aerosol (SOA) producing BVOC classes (isoprene, monoterpenes and sesquiterpenes). The reconstructions predicted that global isoprene emissions have decreased (land-use changes to crop/grazing land dominate the reduction), while monoterpene and sesquiterpene emissions have increased (temperature increases dominate the increases); however, all three show regional variability due to competition between the various influencing factors. These BVOC changes have largely been anthropogenic in nature, and land-use change was shown to have the most dramatic effect by decreasing isoprene emissions. In this work, we use two modeled estimates of BVOC emissions from the years 1000 to 2000 to test the effect of anthropogenic changes to BVOC emissions on SOA formation, global aerosol size distributions, and radiative effects using the GEOS-Chem-TOMAS global aerosol microphysics model. With anthropogenic emissions (e.g. SO2, NOx, primary aerosols) held at present day values and BVOC emissions changed from year 1000 to year 2000 values, decreases in the number concentration of particles of size Dp > 80 nm (N80) of >25% in year 2000 relative to year 1000 were predicted in regions with extensive land-use changes since year 1000 which led to regional increases in direct plus indirect aerosol radiative effect of >0.5 W m−2 in these regions. We test the sensitivity of our results to BVOC emissions inventory, SOA yields and the presence of anthropogenic emissions; however, the qualitative response of the model to historic BVOC changes remains the same in all cases. Accounting for these uncertainties, we estimate millennial changes in BVOC emissions cause a global mean direct effect of between +0.022 and +0.163 W m−2 and the global mean cloud-albedo aerosol indirect effect of between −0.008 and −0.056 W m−2. This change in aerosols, and the associated radiative forcing, could be a~largely overlooked and important anthropogenic aerosol effect on regional climates.


2011 ◽  
Vol 11 (9) ◽  
pp. 24857-24881 ◽  
Author(s):  
K. Ashworth ◽  
G. Folberth ◽  
C. N. Hewitt ◽  
O. Wild

Abstract. Large-scale production of feedstock crops for biofuels will lead to land-use changes. We quantify the effects of realistic land use change scenarios for biofuel feedstock production on isoprene emissions and hence atmospheric composition and chemistry using the HadGEM2 model. Two feedstocks are considered: oil palm for biodiesel in the tropics and short rotation coppice (SRC) in the mid-latitudes. In total, 69 Mha of oil palm and 92 Mha of SRC are planted, each sufficient to replace just over 1 % of projected global fossil fuel demand in 2020. Both planting scenarios result in increases in total global annual isoprene emissions of about 1 %. In each case, changes in surface concentrations of ozone and biogenic secondary organic aerosol (bSOA) are significant at the regional scale and are detectable even at a global scale with implications for air quality standards. However, the changes in tropospheric burden of ozone and the OH radical, and hence effects on global climate, are negligible. The oil palm plantations and processing plants result in global average annual mean increases in ozone and bSOA of 38 pptv and 2 ng m−3 respectively. Over SE Asia, one region of planting, increases reach over 2 ppbv and 300 ng m−3 for large parts of Borneo. Planting of SRC causes global annual mean changes of 46 pptv and 3 ng m−3. Europe experiences peak monthly mean changes of almost 0.6 ppbv and 90 ng m−3 in June and July. Large areas of Central and Eastern Europe see changes of over 1.5 ppbv and 200 ng m−3 in the summer. That such significant atmospheric impacts from low level planting scenarios are discernible globally clearly demonstrates the need to include changes in emissions of reactive trace gases such as isoprene in life cycle assessments performed on potential biofuel feedstocks.


2018 ◽  
Vol 66 (1-1) ◽  
pp. 42
Author(s):  
Gerardo Umaña-Villalobos ◽  
Aldo Farah-Pérez

Lake Río Cuarto is a meromictic lake at low elevation in the North of Costa Rica. It offers an opportunity to compare its present state with the condition it had when first studied in the late 1970’s and occasional samplings since then. This comparison expects to identify changes that could be attributed to incipient effects of global climate change. We studied the limnology and conditions of its drainage area for three years (2013-2016) to compare with previous data. Vertical profiles of temperature, dissolved oxygen, conductivity, pH, chlorophyll a, dissolved H2S were performed several times per year, for a total of 22 samplings. Aerial photographs taken since 1950 were analyzed to describe land use changes. The lake had a shallow Secchi depth (< 5 m) at all times. It was stratified on all occasions, with a thermocline that fluctuated between 10 and 20 m. It has a monimolimnion, with a chemocline at 14 to 22 m. Below the chemocline it was always anoxic, and during annual partial mixing events in the mixolimnion, oxygen levels decreased compared to stratified periods. There was a continuous presence of H2S from 20 m downwards, with annual fluctuations, being lower during partial mixing events. A peak in chlorophyll was detected on all occasions just below the thermocline. Land use around the lake hasn’t changed much since 1952, when only a rim of tree cover was left around the steep margins of the lake. The lake has maintained its limnological characteristics, with the only exception that it didn’t cooled down to historical levels. This limited response could be the result of the high relative depth and steep margins of the lake, which prevent the downward distribution of heat and keeps the lake in a meromictic state, preventing its mixing for long periods of time.


Sign in / Sign up

Export Citation Format

Share Document