Evidence for a CO increase in the SH during the 20th century based on firn air samples from Berkner Island, Antarctica

Assonov, S. S.; Brenninkmeijer, Carl A. M.; Jöckel, Patrick; Mulvaney, Robert; Bernard, Serge; Chappellaz, J.

doi:10.5194/acp-7-295-2007

Cited by 31 publications

(32 citation statements)

References 45 publications

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“…Other sources of information include the use of CH 4 concentrations in ice cores (Ferretti et al, 2005) and firn air samples, although it is uncertain to what degree the most recent part of the record is representative for current conditions. These studies show an increase over the recent decades for both the Northern Hemisphere (Wang et al, 2012) and Southern Hemisphere (Assonov et al, 2007), and at this point we cannot reconcile the differences found in the various records indicating that uncertainty remains substantial.…”

Section: Discussionmentioning

confidence: 79%

“…Observations of CH 4 concentrations and its isotopic ratio also indicated an increase; however, this increase continued until the present without a peak in the 19th century (Ferretti et al, 2005). This pattern is also observed in firn air samples in both the Northern Hemisphere (Wang et al, 2012) and Southern Hemisphere (Assonov et al, 2007).…”

Section: Introductionmentioning

confidence: 77%

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Historic global biomass burning emissions for CMIP6 (BB4CMIP) based on merging satellite observations with proxies and fire models (1750–2015)

et al. 2017

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Abstract. Fires have influenced atmospheric composition and climate since the rise of vascular plants, and satellite data have shown the overall global extent of fires. Our knowledge of historic fire emissions has progressively improved over the past decades due mostly to the development of new proxies and the improvement of fire models. Currently, there is a suite of proxies including sedimentary charcoal records, measurements of fire-emitted trace gases and black carbon stored in ice and firn, and visibility observations. These proxies provide opportunities to extrapolate emission estimates back in time based on satellite data starting in 1997, but each proxy has strengths and weaknesses regarding, for example, the spatial and temporal extents over which they are representative. We developed a new historic biomass burning emissions dataset starting in 1750 that merges the satellite record with several existing proxies and uses the average of six models from the Fire Model Intercomparison Project (FireMIP) protocol to estimate emissions when the available proxies had limited coverage. According to our approach, global biomass burning emissions were relatively constant, with 10-year averages varying between 1.8 and 2.3 Pg C yr −1 . Carbon emissions increased only slightly overPublished by Copernicus Publications on behalf of the European Geosciences Union. the full time period and peaked during the 1990s after which they decreased gradually. There is substantial uncertainty in these estimates, and patterns varied depending on choices regarding data representation, especially on regional scales. The observed pattern in fire carbon emissions is for a large part driven by African fires, which accounted for 58 % of global fire carbon emissions. African fire emissions declined since about 1950 due to conversion of savanna to cropland, and this decrease is partially compensated for by increasing emissions in deforestation zones of South America and Asia. These global fire emission estimates are mostly suited for global analyses and will be used in the Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations.

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Section: Discussionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 77%

Historic global biomass burning emissions for CMIP6 (BB4CMIP) based on merging satellite observations with proxies and fire models (1750–2015)

et al. 2017

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“…A key discrepancy is that the CH 4 data (Ferretti et al, 2005), which has been confirmed by Mischler et al (2009), supports the relatively high values in the first millennium, but does not support the second peak around 1900 AD. Instead, it peaks in current times with higher rates than in the previous 2000 yr. Firn air samples focusing on recent decades also find an increasing trend, both in the Northern (Wang et al, 2012) and Southern (Assonov et al, 2007) Hemisphere. These findings are contradictory to the results of Marlon et al (2008) and Wang et al (2010).…”

Section: G R Van Der Werf Et Al: Pre-industrial Biomass Burning Emmentioning

confidence: 93%

What could have caused pre-industrial biomass burning emissions to exceed current rates?

Werf¹,

Peters

Leeuwen³

et al. 2013

Clim. Past

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Abstract. Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary landscape fire emissions and the TM5 chemical transport model driven by present-day atmospheric transport and OH concentrations, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various landscape biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g., fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data, all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture exceeding current levels, despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation; satellite data indicates that the majority of savannas have not burned in the past 10 yr, even in Africa, which is considered "the burning continent". Although we have not considered increased charcoal burning or changes in OH concentrations as potential causes for the elevated CO concentrations found at SPO, it is unlikely they can explain the large increase found in the CO concentrations in ice core data. Confirmation of the CO ice core data would therefore call for radical new thinking about causes of variable global fire rates over recent centuries.

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“…On the other hand CAM-chem seems to slightly overestimate ozone in the mid-1990s. In addition, analysis of the reconstructed CO change by Assonov et al [2007] indicates an increase of approximately 40% between 1900 and 2000; this is quite well matched by the model results ( Figure S2), especially for CAM-chem. Additional discussions on CO are given by Lamarque et al [2010].…”

Section: Surface Concentrations Over Antarcticamentioning

confidence: 99%

Understanding the drivers for the 20th century change of hydrogen peroxide in Antarctic ice-cores

Lamarque

McConnell

Shindell

et al. 2011

Geophys. Res. Lett.

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[1] Observations and model simulations of an Antarctic icecore record of hydrogen peroxide during the last ∼150 years are analyzed. The observations indicate a relative increase in hydrogen peroxide by approximately 50% since 1900, with most of the change since the early 1970s. Using two model simulations spanning 1850 to present, we show that the modeled relative change in annual-mean surface hydrogen peroxide parallels the equivalent signal from the ice core record. In addition, we show that this relative change can be explained by the relative changes in tropospheric ozone concentration and mostly in ozone photolysis rates (J(O 1 D)). The simulated signal is therefore intimately related to the changes in stratospheric ozone associated with increases in chlorofluorocarbons; this is further demonstrated using total ozone column observations and the associated observed change in ice-core hydrogen peroxide.

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Evidence for a CO increase in the SH during the 20th century based on firn air samples from Berkner Island, Antarctica

Cited by 31 publications

References 45 publications

Historic global biomass burning emissions for CMIP6 (BB4CMIP) based on merging satellite observations with proxies and fire models (1750–2015)

Historic global biomass burning emissions for CMIP6 (BB4CMIP) based on merging satellite observations with proxies and fire models (1750–2015)

What could have caused pre-industrial biomass burning emissions to exceed current rates?

Understanding the drivers for the 20th century change of hydrogen peroxide in Antarctic ice-cores

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