WORKPACKAGES

HUMAN FOOTPRINTS

Mitigating the GHG emissions, by protecting climate regulating services is one of the action necessary for reducing the climate risks. Increased pressure on ecosystems deriving from human activities across terrestrial, marine and freshwater ecosystems can potentially increase emissions threatening climate regulating services, as well as GHG exchange.

Through co-production workshops we wish to bring the human perspectives, pressures and impact into a holistic system approach. We wish to develop tools to identify and visualize human footprints and a tool to identify and mitigate pressures that human induce across ecosystems.

 

 

The role of human footprints and pressures in mitigating risks has been poorly explored. Increased pressure on ecosystems deriving from human activities can potentially increase emissions threatening important climate regulating services. Thus, there is a need to understand how human pressure impact these services and hereby the GHG cycles. Through a consideration of the great value climate regulating services encompass, we emphasizes the importance of dialogue and collaboration between those developing, providing and using climate information in decision-making, businesses and daily life and hence co-design is a part of the research  design in GreenFeedBack.

The role of human footprints and pressures in mitigating risks has been poorly explored. Increased pressure on ecosystems deriving from human activities can potentially increase emissions threatening important climate regulating services. Thus, there is a need to understand how human pressure impact these services and hereby the GHG cycles. Through a consideration of the great value climate regulating services encompass, we emphasizes the importance of dialogue and collaboration between those developing, providing and using climate information in decision-making, businesses and daily life and hence co-design is a part of the research  design in GreenFeedBack.

Stakeholder engagement can strengthen our knowledge and data on where and how human footprints have, is and will impact marine, terrestrial and freshwater system. Co-design can also facilitate a good and transparent communication of scientifically based information and products thereby enhancing users’ knowledge and understanding about the impacts of climate on their decisions and actions. Climate services need to be provided to users in a seamless manner and, most of all, respond to user requirements. Co-design can be highly useful for reaching these requirements and to enable the dialogue and collaboration between multiple actors and scientists to generate credible, salient and legitimate knowledge and solutions for climate mitigation. To serve this purpose, we will develop a traffic light toolkit to communicate the mitigation of the threats to climate regulating services.

Human activities influence the natural ecosystems and thus the cycle and fluxes of C, nitrogen (N) and GHGs. The figure above shows the human activities (human footprint), how they influence the ecosystems and how they affect the GHG cycle and fluxes.

TERRESTRIAL

GHG fluxes and carbon cycle

We wish to enhance knowledge of the effects from a changing
climate and increasing frequency of extreme events at high northern latitudes on terrestrial GHG exchanges and C-cycle. We will seek a better understanding of both short- and long-term responses, by experimental and observational approaches, remote sensing, data assimilation and process-based ecosystem modelling.

Knowledge of  feedbacks in the boreal zone, the Arctic and the permafrost regions under a changing climate is highly needed to
improve our understanding and our ability to  project future scenarios of biosphere-atmosphere GHG exchanges GreenFeedBack will enhance our knowledge of changes in GHG fluxes induced by changing climate, human activities and extreme events based on analysis of existing data sets, new targeted measurements of GHG concentrations, fluxes and the variables affecting the fluxes. 

 

Ongoing and expected future changes in climate will likely trigger complex and irreversible responses in permafrost environments impacting vegetation and soil dynamics as well as the C sink-source functioning. Additionally, heat waves, extreme precipitation events and other natural disturbances may be taking place with increasing frequency in a changing climate likely effecting the resilience of the ecosystems. Extreme events have been found to cause more landscape alterations in a single year than multiple years of subtle warming. For example, vegetation and its dynamics will be highly affected by drought, soil hypoxia, and more frequent fires. Through observations and model simulations WP3 will therefore focus on short- and long-term impact of extreme events on C-cycling in high northern latitudes.

One of the research and monitoring sites is Zackenberg. This localitiy is an undisturbed ecosystem characterized by water-saturated organic soils with an abundant snowmelt water supply and with large amounts of carbon stored in the ground. We measure in Zackenberg, and other sites in Greenland and the Arctic in general, to have a better understanding of the carbon (C) cycle responses affected by climate change. With an eddy covariance method we are able to measure the balance between C uptake (via photosynthesis) and release (via ecosystem respiration). This is a very delicate (and dynamic) balance that changes over time as a response to meteorological forcing such as temperature, precipitation, and radiation, but also due to local changes in e.g. vegetation dynamics, nutrient availability, herbivore interactions, or permafrost thawing.

In addition, the nutrient cycle may be affected by permafrost thaw, prolonged soil warming and enhanced deposition, which may increase the N availability having significant implications for plant growth and carbon storage. Resulting changes to the land surfaces through permafrost degradation, vegetation shifts and changes in rain/snow ratio will impact landscape scale GHG exchanges, which all will be assessed in WP3.

FRESHWATER

GHG EXCHANGE and carbon cycle

We wish to improve the understanding of the processes driving high-latitude freshwater systems-atmosphere fluxes of GHGs, as well as the lateral transport, transformation of carbon and nutrient loads along the land-to-ocean aquatic continuum, to reduce the uncertainties in GHG budgets and trends at national, regional and continental scales

 

In this way we wish to identify major feedbacks related to climate change and human induced pressures and impacts.

Inland waters play a pivotal role in the global C cycle by storing, transporting, or transforming inorganic and organic carbon components along the hydrologic continuum linking the terrestrial systems to oceans. In Earth system science, freshwater bodies are often overlooked even though they are a substantial source of CO2 and methane to the atmosphere. 

 

Lakes and ponds are shown to be a large natural source of methane to the atmosphere and are suggested to be the dominant source in high northern latitudes and lakes can also emit a significant amount of CO2 on a landscape scale. About 50% of lakes and wetlands occur in northern high latitudes and these systems are particularly vulnerable due to the amplification of warming in the Arctic region and the enhancement in the eutrophication status which affects the GHG emission. Rising temperature has been confirmed to stimulate the release of nutrients from sediments via mineralization, consequently boosting the eutrophication state of freshwaters and likely methane release to the atmosphere. Longer ice-free periods could increase the GHG emissions from northern freshwater systems. In addition to temperature, climate change will induce increasing rainfall at higher latitudes, which can increase runoff, leading to higher nutrient inputs.

In GreenFeedBack we will characterize the sources, lateral transport and transformation of carbons compounds along the land-ocean-aquatic-continuum, based on analysis of data from existing infrastructures and new dedicated field studies. We will assess the drivers and processes controlling the air-water GHG exchange and quantify the local and regional effects of climate-freshwater system feedback using new innovative data analysis techniques and advanced ecosystem models. 

 

Knowledge of  feedbacks in the boreal zone, the Arctic and the permafrost regions under a changing climate is highly needed to improve our understanding and our ability to  project future scenarios of biosphere-atmosphere GHG exchanges GreenFeedBack will enhance our knowledge of changes in GHG fluxes induced by changing climate, human activities and extreme events based on analysis of existing data sets, new targeted measurements of GHG concentrations, fluxes and the variables affecting the fluxes.

OCEAN

GHG EXCHANGE and carbon cycle

We wish to enhance the understanding of air-sea exchange of GHG in ocean and coastal areas affected by sea ice and glacier runoff and riverine inputs. Notably, we plan to review the Arctic Ocean carbon budget in Earth System Models using an improved parametrisation air-sea exchange and, accounting for air-ice and coastal shelf exchange processes. Thanks to models and new observations, we will evaluate the feedbacks of the Arctic Ocean CO2 sink to ongoing climate change and assess the future Arctic CO2 sink.

Long terms changes have already started in the Arctic (sea ice shrinkage, ocean freshening, ocean acidification), and climate models predict change in snow precipitation and the transition towards rainfall, as well as an increase in freshwater runoff into the ocean. We will investigate the impact of these long-term changes on air-sea and air-ice CO2 and CH4 exchange and the CO2 uptake of the Arctic ocean. We are also interested in the response (feedback) of the Arctic Ocean CO2 sink and CH4 source to short-term climate events such as storms or heat waves and the impact of human activities (e.g. shipping aquaculture, mining, hydroelectricity reservoir and industries) on the regional marine CO2 uptake and CH4 release.

Based on existing and new data of CO2 and CH4 fluxes and underwater concentrations we will improve parameterisations of air-sea and air-ice gas exchange to provide a robust quantification of the Arctic marine CO2 sink, and potential source and sinks of CH4 and N2O.

In WP5 we will enhance our understanding of C cycling in coastal-shelf areas and improve the description of exchange processes from coastal and shelf areas to the open ocean in Earth System Models. We will evaluate the feedbacks of the Arctic Ocean CO2 sink to short-term extreme events (storm, continental and marine heat waves) and long-term changes (sea ice shrinkage, ocean freshening, ocean acidification) and assess the future Arctic marine CO2 sink

Global earth system perspective and feedbacks

We wish to enhance understanding of feedback processes on the global scale, through the implementation of improved process understanding into an Earth system modelling framework. Particular focus will be on response of GHG cycles from extreme conditions. To understand the relative roles and interactions between different feedbacks and different timescales and provide improved projections (including extreme events) and scenarios toward stabilized global temperatures.

Oceans, inland waters and terrestrial ecosystems respond to climate change generating Earth System feedbacks, and can dampen or amplify global and regional climate change. Potentially, climate extremes can have a substantial impact on climate-carbon feedbacks.

 

We will evaluate the combined impacts of the various systems in response to climate change and extreme events, in addition to the relative importance of the respective processes using a common framework. The common framework will be an advanced version of the European ESM EC-Earth, which we will complement with a budgeting framework for the GHGs for a range of timescales. Several studies indicate that the combined response of the carbon cycle to climate change enhances warming via positive feedback, and many studies have been conducted to identify the causes of these feedbacks although there is a large uncertainty about the magnitude of the enhancement.

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