Petroleum exploration increases methane emissions from northern peatlands

Maria Strack,Bin Xu,Julie Lovitt,Saraswati Saraswati,Gregory J Mcdermid,Mir Mustafizur Rahman,Shari Hayne

doi:10.1038/s41467-019-10762-4

Abstract

Peatlands are globally significant sources of atmospheric methane (CH4). In the northern hemisphere, extensive geologic exploration activities have occurred to map petroleum deposits. In peatlands, these activities result in soil compaction and wetter conditions, changes that are likely to enhance CH4 emissions. To date, this effect has not been quantified. Here we map petroleum exploration disturbances on peatlands in Alberta, Canada, where peatlands and oil deposits are widespread. We then estimate induced CH4 emissions. By our calculations, at least 1900 km2 of peatland have been affected, increasing CH4 emissions by 4.4–5.1 kt CH4 yr−1 above undisturbed conditions. Not currently estimated in Canada’s national reporting of greenhouse gas (GHG) emissions, inclusion would increase current emissions from land use, land use change and forestry by 7–8%. However, uncertainty remains large. Research further investigating effects of petroleum exploration on peatland GHG fluxes will allow appropriate consideration of these emissions in future peatland management.

Highlights

Peatlands are globally significant sources of atmospheric methane (CH4)
In order to estimate the potential impact of seismic exploration on CH4 emissions in Alberta, we used data on human disturbances from the Alberta Biodiversity Monitoring Institute’s (ABMI) Human Footprint Inventory[27] and information on wetlands from Alberta Environment and Parks’ Merged Wetland Inventory[28] (Fig. 2; see details in Methods)
There are very few studies on the effect of seismic lines on peatland carbon and greenhouse gas (GHG) exchange[10] or how this will contribute to anthropogenic radiative forcing[32]

Summary

Introduction

Extensive geologic exploration activities have occurred to map petroleum deposits In peatlands, these activities result in soil compaction and wetter conditions, changes that are likely to enhance CH4 emissions. Alberta has important conventional oil and natural gas and shale gas deposits[4] These landscapes contain areas of dense peatland cover[5]. There is evidence of soil compaction when lines have been used repeatedly[20] and lowering of the surface elevation and flattening of microtopography even on LIS lines in peatlands[21] This results in persistent changes in vegetation community[20,22,23] and shallower water table (WT) position[20,21,24]. The objective of this study is to estimate the impact of seismic lines on peatland

Objectives

Methods

Results

Conclusion