Expert assessment of risks posed by climate change and anthropogenic activities to ecosystem services in the deep North Atlantic

Sustainable development of the ocean is a central policy objective in Europe through the Blue Growth Strategy and globally through parties to the Convention on Biological Diversity. Achieving sustainable exploitation of deep sea resources is challenged by the huge uncertainty around the many risks posed by human activities on these remote ecosystems and the goods and services they provide.We used a Delphi approach, an iterative expert-based survey process, to assess risks to ecosystem services in the North Atlantic Ocean from climate change (water temperature and ocean acidification), the blue economy (fishing, pollution, oil and gas activities, deep seabed mining, maritime and coastal tourism and blue biotechnology), and their cumulative effects. Ecosystem services from the deep sea identified through the Millennium Ecosystem Assessment framework were presented in an expert survey to assess the impacts of human drivers on these services. The results from this initial survey were analyzed and then presented in a second survey. The final results based on 55 expert responses indicated that pollution and temperature change each pose high risk to more than 28% of deep-sea ecosystem services whilst ocean acidification, and fisheries both pose high risk to more than 19% of the deep-sea ecosystem services. Services considered to be most at risk of being impacted by anthropogenic activities were biodiversity and habitat as supporting services, biodiversity as a cultural service, and fish and shellfish as provisioning services. Tourism and blue biotechnology were not seen to cause serious risk to any of the ecosystem services. The negative impacts from temperature change, ocean acidification, fishing, pollution, and oil and gas activities were deemed to be largely more probable than their positive impacts. These results expand our knowledge of how a broad set of deep-sea ecosystem services are impacted by human activities. Furthermore, the study provides input in relation to future Abstract 15 Sustainable development of the ocean is a central policy objective in Europe through the Blue 16 Growth Strategy and globally through parties to the Convention on Biological Diversity. 17 Achieving sustainable exploitation of deep sea resources is challenged by the huge uncertainty 18 around the many risks posed by human activities on these remote ecosystems and the goods 19 and services they provide.We used a Delphi approach, an iterative expert-based survey process, 20 to assess risks to ecosystem services in the North Atlantic Ocean from climate change (water 21 temperature and ocean acidification), the blue economy (fishing, pollution, oil and gas 22 activities, deep seabed mining, maritime and coastal tourism and blue biotechnology), and their 23 cumulative effects. Ecosystem services from the deep sea identified through the Millennium 24 Ecosystem Assessment framework were presented in an expert survey to assess the impacts of 25 human drivers on these services. The results from this initial survey were analyzed and then 26 presented in a second survey. The final results based on 55 expert responses indicated that 27 pollution and temperature change each pose high risk to more than 28% of deep-sea ecosystem 28 services whilst ocean acidification, and fisheries both pose high risk to more than 19% of the 29 deep-sea ecosystem services. Services considered to be most at risk of being impacted by 30 anthropogenic activities were biodiversity and habitat as supporting services, biodiversity as a 31 cultural service, and fish and shellfish as provisioning services. Tourism and blue biotechnology 32 were not seen to cause serious risk to any of the ecosystem services. The negative impacts from 33 temperature change, ocean acidification, fishing, pollution, and oil and deemed to be largely more probable than their positive impacts. These results expand our 35 knowledge of how a broad set of deep-sea ecosystem services are impacted by human activities. Furthermore, the study provides input in relation to future priorities regarding research in the 37 Atlantic deep sea.

activities, deep seabed mining, maritime and coastal tourism and blue biotechnology), and their 23 cumulative effects. Ecosystem services from the deep sea identified through the Millennium 24 Ecosystem Assessment framework were presented in an expert survey to assess the impacts of 25 human drivers on these services. The results from this initial survey were analyzed and then 26 presented in a second survey. The final results based on 55 expert responses indicated that 27 pollution and temperature change each pose high risk to more than 28% of deep-sea ecosystem 28 services whilst ocean acidification, and fisheries both pose high risk to more than 19% of the 29 deep-sea ecosystem services. Services considered to be most at risk of being impacted by 30 anthropogenic activities were biodiversity and habitat as supporting services, biodiversity as a 31 cultural service, and fish and shellfish as provisioning services. Tourism and blue biotechnology 32 were not seen to cause serious risk to any of the ecosystem services. The negative impacts from 33 temperature change, ocean acidification, fishing, pollution, and oil and gas activities were Although our oceans and seas are "out of sight, out of mind" to much of society, we are 59 becoming increasingly aware of the fact that marine ecosystems are highly impacted by climate 60 change and our endeavours to exploit living and non-living marine resources (Halpern et al. 61 2008). Despite their remoteness and difficulty to access, the demise of the deep ocean is 62 particularly noteworthy as it is the largest but least known biome on Earth. The deep North 63 Atlantic Ocean has been studied for the last two centuries, and is now known to harbour 64 ecosystems that support a biologically rich variety of life that perform key functions to global 65 biogeochemical cycles, e.g., cycling of primary production, carbon and nutrients from the ocean  Complex three-dimensional ecosystems formed by cold-water corals, sponges, and 68 topographically complex seamounts and hydrothermal vents not only support high and 69 sometimes unique or endemic species, but these ecosystems also provide many ecosystem 70 goods and services which contribute to maritime economic activities that underpin the socio-

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In addition to climate change and historic types of resource exploitation dating back to antiquity 84 (fisheries) and into the last century (oil and gas), the European Commission Blue Growth 85 Strategy seeks to support sustainable growth in the North Atlantic across five sectors: 86 aquaculture, maritime and coastal tourism, blue biotechnology, ocean energy and seabed 87 mining (EC 2012). This strategy may pose a challenge to the business and policy objectives 88 seeking to balance societal needs with environmental sustainability.

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One way to consider the balance between the blue growth economic agenda and sustainability 90 is to assess the potential impacts or risks posed by different forms of human activity on the 91 ecosystem services provided by the deep sea. It may also be assumed that an assessment of 92 impacts and risks will inform marine spatial planning (MSP). Marine spatial planning calls for 93 due regard in relation to various pressures from human activities and climate change on marine 94 ecosystems, their services and economic development (Ntona and Morgera 2018). These 95 impacts affect and pose risks in relation to services that the ecosystems provide to humans. In 96 order to assess any form of risk, consequences and probability of hazard occurrences need to 97 be identified. There is a multitude of studies assessing risks of specific activities, such as oil  or ecosystems is often very demanding in itself. Knowledge is limited (particularly so in the 105 deep sea), and the consequences can be highly diverse as well as controversial. Bringing the 106 risk analysis one step further, to ecosystem services, can, therefore, be even more challenging.

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A second issue is; who are the experts that should assess the risk to ecosystem services?

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Although the scientific knowledge can provide expert input regarding risks to ecosystems, it is  In addition, the deep sea is often both spatially and temporally distant to the services that 141 humans value, it is, therefore, all the more important to identify the riskiest drivers, and from 142 this provide input into where more work must be done to mitigate or adapt to the risks involved.

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In this paper, we use a Delphi survey approach to assess risks to deep sea ecosystem services 144 within the North Atlantic. This is in contrast to previous work which has considered effects on

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We used a Delphi survey to assess risks of human drivers to deep-sea ecosystem services. The  Table 1). Though the Delphi process is considered more reliable than a single survey, the method has 185 been critiqued for group pressure, rather than knowledge development, leading to consensus in 186 repeated surveys (Woudenberg 1991). The Delphi approach is however also roundly defended,  Table 2).  Risk is the product of two entities, consisting of 1) some measure of the consequences of an 224 occurrence and 2) the likelihood that the occurrence will take place. Usually, the occurrence is 225 defined as some hazard. However, occurrences need not be hazards causing negative effects, however, be problematic, and must be used with caution (Cox Jr. 2008). We do not however 241 estimate a risk measure, but rather present the graphical combination of likelihood and severity.

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Risk assessment, in general, can also be critiqued based on normative aspects and in relation to

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The ecosystem services at low risk from a high number of human drivers are waste disposal 320 and raw materials (both provisioning ecosystem services) and a supporting ecosystem service 321 of primary production. None of these three ecosystem services is at high risk from human 322 drivers.

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The second objective was to assess the level of risk associated with the human drivers 324 specifically. In Figure 4 we illustrate the different human drivers, and how they impact on the 325 21 ecosystem services as regards high, medium and low risks. This is used to identify the 326 anthropogenic activities (human drivers) that are perceived to have the highest level of risk to 327 ecosystem services.  can be seen in Table 3. We also observe that the variation only declined in the second round for

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The number of human drivers that pose high risk increases from three to six for biodiversity (as 373 a supporting service), two to six for habitat, three to five for biodiversity (as a cultural service) 374 and two to four for fish/shellfish. However, using simple t-tests we find no statistically  We also assessed whether perceptions differed from the first survey to the second regarding the 389 average number of human drivers posing high risk to ecosystem services, for those services that 390 are perceived to be at high risk from at least one human driver, as shown in Table 4. Using t-391 tests, we reject the null hypothesis that the two conditional means are different, at the 5% level. Although the rankings of ecosystem services in terms of high risk remain almost the same in  Table 3).

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After the risk assessment we asked about respondents' certainty in their responses using a scale 406 from 1 to 5 (with 1 being very uncertain and 5 being very certain). The median level of the 407 certainty score is 3 for both surveys, but the average certainty increased slightly from 2.56 in 408 the first survey to 2.82 in the second round. A t-test found not statistical difference (at 5% level) 409 between the expressed certainty in the two surveys. 410 We also asked the respondents to identify which ecosystem services that they are certain about.

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The main ecosystem services identified here include biodiversity, climate regulation and  Some propose that other frameworks should be developed to provide alternative perspectives. provide the greatest positive effects and likelihoods, with oil/gas and mining following them.

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In concluding, newer blue growth industries do not seem to involve the greatest risk to 457 ecosystem services. Indeed, it seems to be the larger global problems of climate, pollution and 458 fisheries that are perceived to pose the highest risks to marine ecosystem services.

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The main contribution of this study is to focus on risk to ecosystem services, rather than marine    The median scores we presented for both effects and likelihoods separately in Tables 1 and 2   770 above, were combined for risk assessment using the risk assessment matrix in Figure 2 below. 771 In the risk assessment matrix, high effects and high likelihoods indicate high risk and low 772 effect and low likelihoods indicate low risk. If we use a risk reporting matrix such as the one 773 given in Figure 2 below, we find that there are only services at high risk level in our study 774 where the median likelihood and effect are (4,4). I.e. there are no cases of the remaining red 775 areas in the figure below.