Costs and benefits of protecting linear landscape elements: Applying systematic conservation planning on a case study in the Netherlands.

Protecting and increasing linear landscape elements (LLEs) in agricultural lands is regarded as a possible solution for a transition to a more biodiverse agricultural system. However, optimizing the spatial configuration of LLEs protected areas is challenging, especially given the demand for land for food production. Systematic Conservation Planning (SCP) can address this challenge, by prioritizing cost-efficient protection areas. We used a SCP approach to look at the LLEs network in the Province of Noord-Brabant in the Netherlands, identifying the possible trade-off between optimizing species conservation, costs and the monetary values of ecosystem services (ES). For this we defined two scenarios. One scenario focuses on achieving species conservation targets at the minimum cost, and the other focuses on achieving targets while maximizing the benefits provided by ES. For each scenario, we further developed two land-management options, namely land-sharing and land-sparing. For each solution, we tested their cost-effectiveness by calculating implementation costs, economic benefits provided by ES, and cost/benefit ratios. First, our scenario analysis indicates that the economic benefits provided by ES always outweigh the implementation costs. Second, it shows that including ES as co-benefits in SCP (Maximize ES Scenario) yields more cost-efficient conservation solutions. Third, both land-sharing and land-sparing are possible cost-efficient approaches to achieve conservation targets. Our results are spatially explicit and identify crucial habitat areas for the conservation of the selected species, which represent 12-20% of the current unprotected network of LLEs. Our findings showcase net economic benefit of conserving species and LLEs, thus representing an additional reason for biodiversity conservation.

Extending shared socio-economic pathways for pesticide use in Europe: Pest-Agri-SSPs.

While pesticides are essential to agriculture and food systems to sustain current production levels, they also lead to significant environmental impacts. The use of pesticides is constantly increasing globally, driven mainly by a further intensification of agriculture, despite stricter regulations and higher pesticide effectiveness. To further the understanding of future pesticide use and make informed farm-to-policy decisions, we developed Pesticide Agricultural Shared Socio-economic Pathways (Pest-AgriSSPs) in six steps. The Pest-Agri-SSPs are developed based on an extensive literature review and expert feedback approach considering significant climate and socio-economic drivers from farm to continental scale in combination with multiple actors impacting them. In literature, pesticide use is associated with farmer behaviour and practices, pest damage, technique and efficiency of pesticide application, agricultural policy and agriculture demand and production. Here, we developed PestAgri-SSPs upon this understanding of pesticide use drivers and relating them to possible agriculture development as described by the Shared Socio-economic Pathways for European agriculture and food systems (Eur-Agri-SSPs).The Pest-AgriSSPs are developed to explore European pesticide use in five scenarios representing low to high challenges to mitigation and adaptation up to 2050. The most sustainable scenario (Pest-Agri-SSP1) shows a decrease in pesticide use owing to sustainable agricultural practices, technological advances and better implementation of agricultural policies. On the contrary, the Pest-Agri-SSP3 and Pest-Agri-SSP4 show a higher increase in pesticide use resulting from higher challenges from pest pressure, resource depletion and relaxed agricultural policies. Pest-Agri-SSP2 presents a stabilised pesticide use resulting from stricter policies and slow transitions by farmers to sustainable agricultural practices. At the same time, pest pressure, climate change and food demand pose serious challenges. Pest-Agri-SSP5 shows a decrease in pesticide use for most drivers, influenced mainly by rapid technological development and sustainable agricultural practices. However, Pest-Agri-SSP5 also presents a relatively low rise in pesticide use driven by agricultural demand, production, and climate change. Our results highlight the need for a holistic approach to tackle pesticide use, considering the identified drivers and future developments. The storylines and qualitative assessment provide a platform to make quantitative assumptions for numerical modelling and evaluating policy targets.

Achieving net-zero emissions targets: An analysis of long-term scenarios using an integrated assessment model.

More than 100 countries have communicated or adopted new Nationally Determined Contributions (NDCs) and net-zero target pledges. We investigate the impact on global, national, sectoral, and individual greenhouse gas emissions projections under different scenarios based on the announced NDCs and net-zero pledges using the IMAGE integrated assessment model. Our results show that while the net-zero pledges, if implemented, could be an important step forward, they are still not enough to achieve the Paris Agreement goals of well below 2°C and preferably 1.5°C by the end of the century. Still, our net-zero scenarios project significant all-sector decarbonization, in particular, electricity; however, certain sectors like industry and transport prove hard to completely abate.

Development of chemical emission scenarios using the Shared Socio-economic Pathways.

The widespread use of chemicals has led to significant water quality concerns, and their use is still increasing. Hence, there is an urgent need to understand the possible future trends in chemical emissions to water systems. This paper proposes a general framework for developing emission scenarios for chemicals to water using the Shared Socio-economic Pathways (SSPs) based on an emission-factor approach. The proposed approach involves three steps: (i) identification of the main drivers of emissions, (ii) quantification of emission factors based on analysis of publicly available data, and (iii) projection of emissions based on projected changes in the drivers and emission factors. The approach was tested in Europe for five chemical groups and on a national scale for five specific chemicals representing pharmaceuticals, pesticides, and industrial chemicals. The resulting emission scenarios show widely diverging trends of increased emissions by 240% for ibuprofen in SSP3 (regional rivalry) to a 68% decrease for diclofenac in SSP1 (sustainable development) by 2050. While emissions typically decrease in SSP1, they follow the historical trend in SSP2 (middle-of-the-road scenario) and show an increase in the regional rivalry scenario SSP3 for most selected chemicals. Overall, the framework allows understanding of future chemical emissions trends as a function of the socio-economic trends as captured in the SSPs. Our scenarios for chemical emissions can thus be used to model future aqueous emissions to support risk assessment. While the framework can be easily extended to other pharmaceuticals and pesticides, it heavily leans on the availability and quality of historical emission data and a detailed understanding of emission sources for industrial chemicals.

On the optimality of 2°C targets and a decomposition of uncertainty.

Determining international climate mitigation response strategies is a complex task. Integrated Assessment Models support this process by analysing the interplay of the most relevant factors, including socio-economic developments, climate system uncertainty, damage estimates, mitigation costs and discount rates. Here, we develop a meta-model that disentangles the uncertainties of these factors using full literature ranges. This model allows comparing insights of the cost-minimising and cost-benefit modelling communities. Typically, mitigation scenarios focus on minimum-cost pathways achieving the Paris Agreement without accounting for damages; our analysis shows doing so could double the initial carbon price. In a full cost-benefit setting, we show that the optimal temperature target does not exceed 2.5 °C when considering medium damages and low discount rates, even with high mitigation costs. With low mitigation costs, optimal temperature change drops to 1.5 °C or less. The most important factor determining the optimal temperature is the damage function, accounting for 50% of the uncertainty.

Biomass residues as twenty-first century bioenergy feedstock-a comparison of eight integrated assessment models.

In the twenty-first century, modern bioenergy could become one of the largest sources of energy, partially replacing fossil fuels and contributing to climate change mitigation. Agricultural and forestry biomass residues form an inexpensive bioenergy feedstock with low greenhouse gas (GHG) emissions, if harvested sustainably. We analysed quantities of biomass residues supplied for energy and their sensitivities in harmonised bioenergy demand scenarios across eight integrated assessment models (IAMs) and compared them with literature-estimated residue availability. IAM results vary substantially, at both global and regional scales, but suggest that residues could meet 7-50% of bioenergy demand towards 2050, and 2-30% towards 2100, in a scenario with 300 EJ/year of exogenous bioenergy demand towards 2100. When considering mean literature-estimated availability, residues could provide around 55 EJ/year by 2050. Inter-model differences primarily arise from model structure, assumptions, and the representation of agriculture and forestry. Despite these differences, drivers of residues supplied and underlying cost dynamics are largely similar across models. Higher bioenergy demand or biomass prices increase the quantity of residues supplied for energy, though their effects level off as residues become depleted. GHG emission pricing and land protection can increase the costs of using land for lignocellulosic bioenergy crop cultivation, which increases residue use at the expense of lignocellulosic bioenergy crops. In most IAMs and scenarios, supplied residues in 2050 are within literature-estimated residue availability, but outliers and sustainability concerns warrant further exploration. We conclude that residues can cost-competitively play an important role in the twenty-first century bioenergy supply, though uncertainties remain concerning (regional) forestry and agricultural production and resulting residue supply potentials.

Integrated Climate-Change Assessment Scenarios and Carbon Dioxide Removal.

To halt climate change this century, we must reduce carbon dioxide (CO2) emissions from human activities to net zero. Any emission sources, such as in the energy or land-use sectors, must be balanced by natural or technological carbon sinks that facilitate CO2 removal (CDR) from the atmosphere. Projections of demand for large-scale CDR are based on an integrated scenario framework for emission scenarios composed of emission profiles as well as alternative socio-economic development trends and social values consistent with them. The framework, however, was developed years before systematic reviews of CDR entered the literature. This primer provides an overview of the purposes of scenarios in climate-change research and how they are used. It also introduces the integrated scenario framework and why it came about. CDR studies using the scenario framework, as well as its limitations, are discussed. Possible future developments for the scenario framework are highlighted, especially in relation to CDR.

Data for long-term marginal abatement cost curves of non-CO2 greenhouse gases.

This dataset represents long-term marginal abatement cost (MAC) curves of all major emission sources of non-CO2 greenhouse gases (GHGs); methane (CH4), nitrous oxide (N2O) and fluorinated gases (HFCs, PFCs and SF6). The work is based on existing short-term MAC curve datasets and recent literature on individual mitigation measures. The data represent a comprehensive set of MAC curves, covering all major non-CO2 emission sources for 26 aggregated world regions. They are suitable for long-term global mitigation scenario development, as dynamical elements (technological progress, removal of implementation barriers) are included. The data is related to the research article: "Long-term marginal abatement cost curves of non-CO 2 greenhouse gases" [1].

Multi-model comparison of the economic and energy implications for China and India in an international climate regime.

This paper presents a modeling comparison on how stabilization of global climate change at about 2 °C above the pre-industrial level could affect economic and energy systems development in China and India. Seven General Equilibrium (CGE) and energy system models on either the global or national scale are soft-linked and harmonized with respect to population and economic assumptions. We simulate a climate regime, based on long-term convergence of per capita carbon dioxide (CO2) emissions, starting from the emission pledges presented in the Copenhagen Accord to the United Nations Framework Convention on Climate Change and allowing full emissions trading between countries. Under the climate regime, Indian emission allowances are allowed to grow more than the Chinese allowances, due to the per capita convergence rule and the higher population growth in India. Economic and energy implications not only differ among the two countries, but also across model types. Decreased energy intensity is the most important abatement approach in the CGE models, while decreased carbon intensity is most important in the energy system models. The reduction in carbon intensity is mostly achieved through deployment of carbon capture and storage, renewable energy sources and nuclear energy. The economic impacts are generally higher in China than in India, due to higher 2010-2050 cumulative abatement in China and the fact that India can offset more of its abatement cost though international emission trading.

The next generation of scenarios for climate change research and assessment.

Advances in the science and observation of climate change are providing a clearer understanding of the inherent variability of Earth's climate system and its likely response to human and natural influences. The implications of climate change for the environment and society will depend not only on the response of the Earth system to changes in radiative forcings, but also on how humankind responds through changes in technology, economies, lifestyle and policy. Extensive uncertainties exist in future forcings of and responses to climate change, necessitating the use of scenarios of the future to explore the potential consequences of different response options. To date, such scenarios have not adequately examined crucial possibilities, such as climate change mitigation and adaptation, and have relied on research processes that slowed the exchange of information among physical, biological and social scientists. Here we describe a new process for creating plausible scenarios to investigate some of the most challenging and important questions about climate change confronting the global community.

Peaking profiles for achieving long-term temperature targets with more likelihood at lower costs.

How can dangerous interference with the climate system be avoided? Science can help decision-makers answer this political question. Earlier publications have focused on the probability of keeping global mean temperature change below certain thresholds by stabilizing greenhouse gas concentrations at particular levels. We compare the results of such "stabilization profiles" with a set of "peaking profiles" that reduce emissions further after stabilization and thus result in a concentration peak. Given the inertia in the climate system, stabilization profiles lead to ongoing warming beyond 2100 until the temperature reaches equilibrium. This warming partly can be prevented for peaking profiles. In this way, these profiles can increase the likelihood of achieving temperature thresholds by 10-20% compared with the likelihood for the associated stabilization profiles. Because the additional mitigation efforts and thus costs for peaking profiles lie mainly beyond 2100, peaking profiles achieving temperature thresholds with the same likelihood as the original stabilization profile, but at considerably lower cost (up to 40%), can be identified. The magnitude of the cost reductions depends on the assumptions on discounting. Peaking profiles and overshoot profiles with a limited overshoot may, in particular, play an important role in making more ambitious climate targets feasible.