Future vegetation–climate interactions in Eastern Siberia: an assessment of  the competing effects of CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and secondary organic aerosols

Arneth, Almut; Makkonen, Risto; Olin, Stefan; Paasonen, Pauli; Holst, Thomas; Kajos, M. K.; Kulmala, Markku; Maximov, Trofim C.; Miller, Paul A.; Schurgers, Guy

doi:10.5194/acp-16-5243-2016

Cited by 21 publications

(17 citation statements)

References 89 publications

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“…Clear-sky events not only cause the strongest deviations of the local urban climate, but also affect particle nucleation (Dada et al, 2017). Processes of turbulent mixing of atmospheric pollution in cold winter conditions remain a future focus of studies for the international research community (Arnold et al, 2016;Kim et al, 2017). Moreover, warmer climate conditions are Figure 8.…”

Section: Impacts Of a Strong Uhi In Arctic Citiesmentioning

confidence: 99%

Anthropogenic and natural drivers of a strong winter urban heat island in a typical Arctic city

et al. 2018

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Abstract. The Arctic has rapidly urbanized in recent decades with 2 million people currently living in more than a hundred cities north of 65∘ N. These cities have a harsh but sensitive climate and warming here is the principle driver of destructive thawing, water leakages, air pollution and other detrimental environmental impacts. This study reports on the urban temperature anomaly in a typical Arctic city. This persistent warm anomaly reaches up to 11 K in winter with the wintertime mean urban temperature being 1.9 K higher on average in the city center than in the surrounding natural landscape. An urban temperature anomaly, also known as an urban heat island (UHI), was found using remote sensing and in situ temperature data. High-resolution (1 km) model experiments run with and without an urban surface parameterization helped to identify the leading physical and geographical factors supporting a strong temperature anomaly in a cold climate. The statistical analysis and modeling suggest that at least 50 % of this warm anomaly is caused by the UHI effect, driven mostly by direct anthropogenic heating, while the rest is created by natural microclimatic variability over the undulating relief of the area. The current UHI effect can be as large as the projected, and already amplified, warming for the region in the 21st century. In contrast to earlier reports, this study found that the wintertime UHI in the Arctic should be largely attributed to direct anthropogenic heating. This is a strong argument in support of energy efficiency measures, urban climate change mitigation policy and against high-density urban development in polar settlements. The complex pattern of thermal conditions, as revealed in this study, challenges urban planners to account for the observed microclimatic diversity in perspective sustainable development solutions.

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Section: Impacts Of a Strong Uhi In Arctic Citiesmentioning

confidence: 99%

Anthropogenic and natural drivers of a strong winter urban heat island in a typical Arctic city

et al. 2018

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“…In MEGAN2.1, used in this study, CO 2 inhibition is included for isoprene. There are indications that the inhibition also affect monoterpenes and some studies include it also for monoterpenes (Arneth et al, 2016). Including CO 2 inhibition for monoterpenes could have reduced the difference is monoterpene emissions between the FB-ON and FB-OFF simulations and reduced the effect of the feedback.…”

Section: Limitations and Uncertaintiesmentioning

confidence: 99%

BVOC-aerosol-climate feedbacks investigated using NorESM

Sporre¹,

Blichner²,

Karset³

et al. 2018

Preprint

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Abstract. Both higher temperatures and increased CO2 concentrations are (separately) expected to increase the emissions of biogenic volatile organic compounds (BVOCs). This has been proposed to initiate negative climate feedback mechanisms through increased formation of secondary organic aerosol (SOA). More SOA can make the clouds more reflective, which can provide a cooling. Furthermore, the increase in SOA formation has also been proposed to lead to increased aerosol scattering, resulting in an increase in diffuse radiation. This could boost gross primary production (GPP) and further increase BVOC emissions. In this study, we have used the Norwegian Earth System Model (NorESM) to investigate both these feedback mechanisms. Three sets of experiments were set up to quantify the feedback w.r.t. (1) doubling the CO2, (2) increasing temperatures corresponding to a doubling of CO2 and (3) the combined effect of both doubling CO2 and a warmer climate. For each of these experiments we ran two simulations, with identical set-up, except for the BVOC emissions. One simulation was run with interactive BVOC emissions, allowing the BVOC emissions to respond to changes in CO2 and/or climate. In the other simulation, the BVOC emissions were fixed at present day conditions, essentially turning the feedback off. The comparison of these two simulations enable us to investigate each step along the feedback as well as estimate their overall relevance for the future climate. We find that the BVOC feedback can have a significant impact on the climate. The annual global BVOC emissions are up to 63&#8201;% higher when the feedback is turned on compared to when the feedback is turned off, with the largest response when both CO2 and climate are changed. The higher BVOC levels lead to the formation of more SOA mass (max 53&#8201;%), and result in more particles through increased new particle formation as well as larger particles through increased condensation. The corresponding changes in the cloud properties lead to a &#8722;0.43&#8201;W&#8201;m&#8722;2 stronger net cloud forcing. This effect becomes about 50&#8201;% stronger when the model is run with reduced anthropogenic aerosol emissions, indicating that the feedback will become even more important as we decrease aerosol and precursor emissions. We do not find boost in GPP due to increased aerosol scattering on a global scale. Instead, the fate of the GPP seem to be controlled by the BVOC effects on the clouds. However, the higher aerosol scattering associated with the higher BVOC emissions is found to also contribute with a potentially important enhanced negative direct forcing (&#8722;0.06&#8201;W&#8201;m&#8722;2). The global total aerosol forcing associated with the feedback is &#8722;0.49&#8201;W&#8201;m&#8722;2 indicating that it has the potential to offset about 13&#8201;% of the forcing associated with a doubling of CO2.

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“…The response of isoprene emission to changing short-term environmental conditions, such as temperature and light, has been firmly established experimentally (Guenther et al, , 2012. Most of the regional to global studies that have considered BVOC emissions changes have concluded that non-LULC factors, due to climate change, are the largest factor affecting BVOC emissions in the long-term (100 years) periods (Arneth et al, 2016;Sanderson et al, 2003;Wiedinmyer et al, 2006;Xie et al, 2016). The changes are primarily associated with elevated temperature that increases isoprene emission, while elevated CO 2 can inhibit isoprene emission Heald et al, 2009;Tai et al, 2013;Tang et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Regional to Global Biogenic Isoprene Emission Responses to Changes in Vegetation From 2000 to 2015

et al. 2018

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Isoprene, a dominant biogenic volatile organic compound that is mainly emitted by trees, has a significant impact on the atmospheric chemistry. Regional to global changes in biogenic isoprene emission associated with vegetation variations between 2000 and 2015 were estimated using the MEGAN model with satellite land cover data for inputs in this study. The satellite data estimates of land cover changes were compared to results from previous investigators that have either conducted regional studies or have used lower resolution land cover data. The analysis indicates that tree coverage increases of >5% occurred in 13% of locations including in central China and Europe. In contrast, a decrease of >5% was observed in about 5% of locations, especially in tropical regions. The trends in global tree coverage from 2000 to 2015 resulted in a global isoprene emission decrease of only 1.5%, but there were significant regional variations. Obvious decreases in tree coverage in some tropical areas (e.g., Amazon Basin, Western Africa, Southeast Asia) resulted in a ~10% reduction of regional isoprene emission due to agricultural expansion. Distinct increments of isoprene emission (5–10%) were mainly found in Northeast China and India and were associated with afforestation efforts. Deforestation and afforestation associated with managed plantations does not only affect the total forest coverage but also impacts average isoprene emission capacity, which can result in accelerated isoprene emission variations. Consequently, isoprene variation assessments are needed that not only account for changes in vegetation fractions but also consider the changes in plant species compositions of forests and other landscapes.

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Future vegetation–climate interactions in Eastern Siberia: an assessment of the competing effects of CO<sub>2</sub> and secondary organic aerosols

Cited by 21 publications

References 89 publications

Anthropogenic and natural drivers of a strong winter urban heat island in a typical Arctic city

Anthropogenic and natural drivers of a strong winter urban heat island in a typical Arctic city

BVOC-aerosol-climate feedbacks investigated using NorESM

Regional to Global Biogenic Isoprene Emission Responses to Changes in Vegetation From 2000 to 2015

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