1 Introduction

Many advances in reducing CO2 emissions have been made over the previous decades with the viability increase in wind and solar energy, and recently with the dissemination of electric cars, it continues to be difficult to achieve the negative emissions required to maintain the world average temperature increase below 1.5 °C as proposed by the Paris Agreement of UNFCCC [1], especially due to the need for negative emissions to reduce the current atmospheric CO2 concentration. Even if we keep emissions within 1.5 °C, it is expected that the thawing of permafrost will continue to exacerbate the impacts of climate change, with the increase in emissions of CH4 [2,3,4,5].

Reducing CO2 concentration in the atmosphere is the most important solution to climate change. However, if there is an urgent need to cool down the Earth, several geoengineering proposals exist for emergency cooling. The most discussed of these proposals is the injection of particles in the stratosphere to increase the reflection of solar radiation back into space [6,7,8,9,10]. This is a relatively simple and low-cost solution that could reduce key hazards resulted from global warming [11].

Other geoengineering solutions propose to reverse the melting of the Arctic sea ice, by pumping seawater from under the Arctic ice cover to the top of it [12, 13]. Figure 1 represents a barge designed to increase the thickness of the Arctic ice cover. However, this alternative might not result in an overall negative energy budget for the Arctic region. This is because the increase in ice formation will increase the temperature of the atmosphere in the Arctic, which will further contribute to melt the ice cover. Thus, the overall energy budget would be similar to the current energy budget. Other geoengineering proposals are presented in [14].

Fig. 1
figure 1

Method proposed for increasing the thickness of the Arctic ice cover [14, 15]

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The Arctic sea ice forms an insulating layer impeding that the warmth in the Arctic Ocean (at around − 1 °C) is dissipated to the cold atmosphere (average − 20°) and radiated into space. The ice cover contributes to keeping the heat in the Arctic Ocean from escaping into space, as shown in Fig. 2a.

Fig. 2
figure 2

a Thermal insulation potential of ocean ice, b climate model results for short and c longwave radiation in the Arctic region [16] (variable: TOA incoming/outgoing longwave/shortwave radiation, institute: LASG-CESS, model: FGOALS-g2, experiment: rcp45/60/85, realm: Atmosphere, ensemble: r1i1p1), c annual mean net surface heat flux in the Arctic region [17]

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Recent climate models have shown that the increase in solar radiation absorption with the melted Arctic water is slightly higher than the increased longwave irradiation into space, as shown in Fig. 2b [16]. In other words, heat balance in the Arctic region is reached with or without the ice cover, warming up the atmosphere, cooling down the ocean and maintaining the overall heat balance of the Arctic region at equilibrium.

A study by [17] has calculated the net heat flux of the Arctic region (Fig. 2c). In locations covered by ice, the net heat flux loss is around 8 W/m2 smaller when compared to areas not covered by ice. The heat lost into space through longwave radiation in areas without ice cover is higher than the shortwave heat reflected due to the albedo effect in areas with ice. In other words, this study shows that the heat loss by the open oceans and into space is higher than the net increase in solar absorption due to the albedo effect, which would result in a slight negative heat balance, having a small cooling effect to the region as a whole. A comparison between the reduction in albedo effect and the increase in radiation into space applying the proposed strategy in the paper is presented in the next section.

Considering the analysis of these heat balance climate models, this paper argues that if this equilibrium is broken by allowing the warmer North Atlantic Ocean to flow over the Arctic Ocean, the heat balance of the region will considerably shift and much more heat will be loss into space. The temperature of the Arctic atmosphere would considerably increase and also the amount of heat loss by the Arctic Ocean. This would result in an overall increase in the world’s atmospheric temperature and an overall reduction in the world’s ocean temperature. However, the combined atmosphere and ocean temperatures would likely reduce. Given that the temperature of the world’s oceans would cool from its bottom to the surface, due to the higher density of cool seawater, it could take hundreds or thousands of years for the overall world atmosphere temperature to start reducing. This might not, however, result in an overall cooling of the world atmosphere.

This paper shows that the main contributor to impede the rise of the North Atlantic Ocean currents above the Arctic Ocean surface is its lower salinity superficial layer, and proposes three possible strategies for reducing the salinity of the Arctic Ocean, thus allowing the North Atlantic Ocean to flow above it. An example of strategy to achieve this had proposed in the form of a dam across the Bering Strait with a pumping system to direct the less salty Arctic waters to the Pacific Ocean in 1956 by the Soviet Union. This would have required an 80-km-long dam across the Bering Strait and would block the cold Pacific current from entering the Arctic. By pumping low-salinity cold surface water across the dam to the Pacific, warmer and higher salinity seawater from the Atlantic Ocean would be introduced into the Arctic Ocean [18, 19]. Soviet scientists opposed the idea, stating that the sea in the Pacific side of the dam would freeze and become unnavigable year round, and increase the extent of the Gobi and other deserts to the northern Siberia coastline [18].

This paper is divided into five sections. Section 2 presents the methodology of the paper and proposes innovative strategies to increase the salinity of the Arctic Ocean surface. Section 3 compares the different strategies proposed to increase the salinity of the Arctic Ocean surface. Section 4 discusses the benefits and challenges of the methodology of this paper. Section 5 concludes the paper.

2 Methodology

A relevant argument in this paper is that if the Arctic sea ice cover is removed by allowing more superficial North Atlantic water to enter the Arctic, it would result in an overall negative energy budget for the Arctic Ocean, cooling down the oceans. Even though the albedo of the Arctic Ocean would reduce with the sea ice cover melt, reflecting less heat back to space, the increase in temperature with the Northern Atlantic current and heat radiated into space from the Arctic Ocean would be even higher. This paper does not attempt to prove this concept; it shows a simplified heat balance as a demonstration of the concept and strategies to allow the Northern Atlantic current to reach the Arctic Ocean. Considerable future work is required to prove the negative energy balance proposed in this study.

According to [20], the superficial albedo only contributes a maximum of 30% of the top of atmosphere albedo in the Arctic Ocean. This is due to the curvature of the solar radiation, combined with the reflection of the sunlight by clouds. Assuming a yearly heat reaching the Arctic Ocean surface of 160 W/m2 per year [21], and a reduction on albedo of 0.15 with the melting of the sea ice cover [20], results in a heat increase of 24 W/m2. The increase in temperature in the Arctic Ocean increases the heat radiated to space according to Eq. 1 [22].

$$P=\epsilon\sigma AT^4$$
(1)

where P is the longwave radiated heat from heat to space in W/m2, ϵ is the emissivity, assumed to be 0.99 [22]. σ is the Stefan–Boltzmann constant = 5.67 × 10−8 W m−2 K−4 [22]. A is the area available for heat radiation of 1 m2.

T is the average temperature between 1960 and 1970 [23], the temperature required to start cooling the Earth and the temperature of an ice-free Arctic during the winter (suggested by the authors, implementing the solutions proposed in the paper), as shown in Fig. 3.

Fig. 3
figure 3

Average monthly temperature change in the Arctic Ocean in 1960–1970s [23], the temperature required to achieve an equilibrium in heat balance and the temperature assuming no ice cover is formed in the Arctic Ocean during the winter (suggested by the authors, implementing the solutions proposed in the paper) [23]

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Figure 3 compares the average monthly temperature of the Arctic Ocean surface between 1960 and 1970 [23] with two scenarios of possible temperature increases in the Arctic Ocean surface, assuming that the North Atlantic Ocean currents enter the Arctic Ocean. The orange line shows the temperature increase required to allow that the contribution to the increase in longwave radiation to space matches the increase in heat absorption due to the change in albedo, as estimated in Table 1. The gray line shows the proposed temperature of the Arctic Ocean surface, assuming that no ice cover is formed in the Arctic Ocean during the winter, due to the increase in North Atlantic current to the Arctic. As estimated in Table 1, the amount of longwave heat radiated to space will be higher than the contribution from the albedo effect, resulting in a negative heat balance in the region.

Table 1 Heat balance of the Arctic Ocean, comparing the albedo effect with the increase in radiation into space
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Note that this is just a simple representation of the possible future scenarios compared to historical temperatures. In order to properly analyze the proposed future scenarios, existing models could be modified [24, 25] to examine such scenarios. There are a several feedback phenomena that are not included in the simple representation, such as change in cloud formation, precipitation, climate patterns, ocean currents, and their impact albedo and on longwave irradiation to space. Some of these feedbacks are explored in the discussion section.

A major factor that influences the Arctic climate is the salinity profile of the Arctic Ocean, which is governed by the so-called Halocline phenomenon as shown in Fig. 4b. The surface layer of the Arctic Ocean (about 100 m deep) has a lower salinity (around 25 g/l) and density, and it floats above higher-density waters. The lower salinity happens because the Arctic is constantly fed by freshwater input from large Siberian and Canadian rivers (Ob, Yenissei, Lena, Mackenzie) and Greenland’s glaciers. This is combined with the fact that most time of the year, the Arctic Ocean is covered with a layer of ice, which reduces the possibility for the wind on the top of the ice to help mix the less salty surface water with the more salty bottom water.

Fig. 4
figure 4

Cross section of the a temperature and b salinity of the Arctic Ocean [26, 27]

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This layer of less salty cold water has a lower density than that of the North Atlantic Ocean surface water, thus resulting in the warmer currents from the Atlantic to flow below the superficial Arctic Ocean less salty layer. This reduces the potential that the Atlantic Ocean has to warm up the Arctic region, keeping the Arctic ice cover in place. As shown in Fig. 4a, the upper 100 m has a considerably lower salinity than the surroundings, which blocks the warmer Northern Atlantic current to flow above the surface of the Arctic Ocean (Fig. 4b).

Another natural phenomenon that happens in the region is the Halocline, where temperature convection does not happen as the low salinity at the surface does not let the warmer water below to rise (Fig. 4b). Convection eddies caused by the temperature difference between the cold ocean surface and the deep warmer water stop in the Halocline layer, leaving only conduction heat as the upward heat transport mechanism between Atlantic and Surface Arctic waters, which is orders of magnitude smaller than heat transfer by convection. Without the Halocline, there would be more heat transfer between the ocean water layers. The salinity and temperature pattern of the Arctic Ocean can be quite complex, being dependent on the different flows into and out of the Arctic region [18].

Table 2 shows the change in seawater density with changes in salinity and temperature. Assuming an Arctic seawater salinity of 30 g/l and temperature 0 °C (i.e., a density of 1067.28 g/l), the temperature of the North Atlantic with a salinity of 35 g/l would need to be higher than 11 °C to be less dense than the Arctic seawater. This is not the case as the seawater loses heat as it approaches the cold Arctic region. Alternatively, assuming a North Atlantic seawater salinity of 35 g/l and temperature 5 °C, the density of the Arctic Ocean will have to be increased from 30 to 32 g/l so that the North Atlantic Ocean will become less dense than the Arctic and flow above it. On average, if the seawater increases 2 °C and salinity reduces 1 g/l, the density of the seawater remains the same. In other words, an increase in 2 °C has a similar impact on the density of seawater as a reduction in 1 g/l in salinity.

Table 2 Comparison of the influence of temperature and salinity difference on seawater density [28]
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As shown in Fig. 5, there are four contributors to salinity reduction in the Arctic Ocean. The Arctic sea ice cover acts in two main ways to reduce superficial salinity. Firstly, it impedes that the seawater below the ice evaporates, which would increase the salinity of the surface water. Secondly, the ice cover blocks the wind/water interface and, thus, reduces the mixing of the surface waters with the deeper saltier waters. Greenland’s melting contributes to reducing the temperature of the North Atlantic currents and to the reduction in salinity of the Atlantic Ocean. The rivers of Russia, Canada and the USA contribute directly to the reduction of the salinity in the Arctic Ocean due to the dilution of the surface ocean waters.

Fig. 5
figure 5

Northern hemisphere topographic map highlighting the area that contributes to reduce the salinity in the Arctic Ocean, showing the flow balance in the region [29]

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Equation 2 presents the mass balance of the different flows in and out of the Arctic Ocean surface, as described in Fig. 5. Equations 3 and 4 present the seawater salt concentration of the Arctic Ocean surface. These equations are applied to estimate the effectiveness of the proposed strategies to increase the salinity of the Arctic Ocean.

$${F_2} + {F_3} + {F_4} + {P_1} - {E_1} - {F_1} + {S_5} - {M_1} = 0$$
(2)
$${C_{1f}} = \frac{{{O_1} \times {C_{1i}} + \left({{F_2} + {F_3} + {F_4} + {P_1} - {E_1}} \right) \times {C_{fw}} - {F_1} \times {C_{1i}} + {S_5} \times {C_5} - {M_1} \times {C_{1i}} }}{{{O_1} + {F_2} + {F_3} + {F_4} + {P_1} - {E_1} - {F_1} + {S_5} - {M_1}}}$$
(3)
$${C_{1f}} = \frac{{{O_1} \times {C_{1i}} - {F_1} \times {C_{1i}} + {S_5} \times {C_5} - {M_1} \times {C_{1i}} }}{{{O_1} + {F_2} + {F_3} + {F_4} + {P_1} - {E_1} - {F_1} + {S_5} - {M_1}}}$$
(4)

where flows and volumes are presented in Fig. 5. C1i is the initial average salt concentration of the Arctic Ocean surface (100 meters deep), assumed to be 30 g/l. C1f is the average salt concentration of the Arctic Ocean surface (100 meters deep) after sometime of implementing the strategies proposed in this paper in g/l. Cfw is the salt concentration of freshwater, equal to 0 g/l. C5 is the salt concentration of the North Atlantic current, assumed to be 35 g/l.

We argue that if these contributions to salinity reduction of the Arctic Ocean are stopped, increasing the salinity of the Arctic surface from 30 to 34 g/l, the North Atlantic Ocean will flow over the superficial Arctic Ocean, warm up the Arctic region and remove the Arctic ice cover, even through the winter. However, this will depend on the strength of the newly formed currents, which without the less salty seawater blockage could reach all the way to the Beaufort Sea and submerge due to its loss in temperature and flow back to the Atlantic Ocean beneath the warmer current. Note that seawater has a volumetric heat capacity of around 3000 times larger than that of air. In order to increase the salinity of the Arctic Ocean surface, three proposals are detailed below.

2.1 Increasing the salinity of the Arctic Ocean surface

This section presents three strategies to increase the salinity of the Arctic Ocean, and these are presented below. These strategies are then compared with each other in aspects such as amount of freshwater contribution and the amount of energy consumption.

  1. 1.

    Reduce the river flow to the Arctic.

  2. 2.

    Reduce Greenland ice sheet melting.

  3. 3.

    Mix the Arctic Ocean waters.

2.1.1 Reduce the river flows to the Arctic

This is the most straightforward approach to increase the salinity of the Arctic Ocean surface. It consists of reducing the flow of water from the Russian, Canadian and USA Rivers to the Arctic Ocean, as shown in Fig. 6a and b respectively. The most appropriate approach to stop the flow of water in these rivers is to divert the water to water scarce regions, where it could bring financial returns to Russia, Canada and USA, and pay the required infrastructure to transport the water. Fig. 6c presents the water stressed regions of the world that would be benefited from the diversion of water that would be discharged in the Arctic Ocean. The Results section presents a study comparing the flow of major rivers and the energy required to transpose the water to southern basins, where water is scarce.

Fig. 6
figure 6

Proposed supply of water from Canada and Russia to projected water-stressed regions of the world in 2030 [30]

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Engineering projects that have already been proposed are the North American Water and Power Alliance (NAWAPA), a vast series of dams, tunnels and reservoirs designed to move 150 km3 of Arctic meltwater to southern Canada, USA and Mexico [31,32,33]. Soviet engineers and administrators have contemplated diverting some of the water of the Ob and Irtysh to Kazakhstan, Soviet Central Asian republics and to replenish the Aral Sea. During the 1980s, there were considerable discussions between Western and Soviet researchers about the impact of the Siberian river diversion to the Arctic Ice cover, local, regional and global climate [34,35,36,37,38,39]. Social and media pressure contributed to the project’s dissolution, due to the substantial social and environmental impacts resulting from the project [40]. Recently, Russian scientists proposed to reduce the flow of Siberia’s Rivers that have increased (due to the melting of the permafrost) and could upset the salt balance and circulation of the Arctic Ocean, leading to the shutdown of the Gulf Stream that would trigger colder winters across Europe and Siberia [39]. This is exactly what the paper wants to avoid while reducing the flow of Siberian Rivers to the Arctic.

In order to estimate the energy consumption to transpose the water from a basin to another, Eq. 5 is applied. The energy requirement estimate for the transposition assumes the half of the maximum pumping head. This is because the water precipitation is distributed at different heights in the basin. The total pumping head assumes the difference in height between the Arctic Ocean (0 m) and the minimum required head to transpose water to the basin in the South. The data utilized in this analysis are taken from [41]. The average river flow discharged to the Arctic Ocean was taken from [42]. Note that there is the possibility that some of the water transposed could generate electricity in the basin to where the water was transposed to; however, this is not considered in this paper.

$${E_T} = {F_T} \times d \times h/2 \times a$$
(5)

where \(E_{T}\) is the energy required to mix the superficial and deep Arctic Ocean waters (J). \(F_{T}\) is the average river flow to be transposed (m3/s). \(d\) is the density of water (1.000 kg/m3). \(h\) is the height required to transpose the water to the basin in the South (in meters). \(a\) is the acceleration of gravity (9.81 m/s2).

2.1.2 Reduce Greenland ice sheet melting

An important step to increase the salinity of the Arctic Ocean surface and the temperature of the North Atlantic current is to reduce the Greenland ice sheet melting. Approaches to accomplish this have been proposed in [43,44,45]. Moore et al. [45] and Wolovick and Moore [44] propose three approaches to reduce Greenland ice sheet melting, reducing the flow of water under the ice sheets, so that it will reduce its speed, build structures to contain the flow of the ice sheets and create dams to restrict the flow of warmer seawater to contact the ice sheet. Hunt and Byers 2018 proposes the creation of floating barriers instead of dams and estimate the costs of them and their impact on ice melting and sea level rise. The most convenient approaches for this project are the dam and barriers as represented in Fig. 7. The estimated Greenland ice sheets melting rate was taken from Romanovsky et al.

Fig. 7
figure 7

a Longitudinal representation of the barriers and dams in front of Greenland glaciers and proposed b barriers and c dams to reduce ice melting in Greenland [43]

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One issue to notice is that with the increase in the North Atlantic current entering the Arctic Ocean will considerably increase the temperature of the Arctic atmosphere. This could increase the melting of Greenland ice contributing to reduce the salinity of the Arctic Ocean and cooling down the North Atlantic current, weakening it and increasing sea level rise. However, without the barriers, Greenland would melt much faster than if barriers are added. Even if it is possible to considerably reduce the melting of Greenland ice, this is not a long-term solution, given that Greenland would not be able to store all inlet ice forever. Even with the barriers, after several hundred or thousand years, the glaciers will overflow the Greenland coast and reach the Arctic Ocean and contribute to more freshwater to the Arctic Ocean surface.

2.1.3 Mix Arctic ocean waters

If the two alternatives above do not prove to be technically, economically and/or environmentally viable, a further alternative would be to pump the less salty water from the Arctic Ocean surface to 1 km depth in the Arctic Ocean, particularly in the Beaufort Sea, whose surface waters have one of the lowest salinity. The less salty and less dense water at 1 km depth will rise; however, the less dense water will mix with the deep water and will not return to the surface. The depth in which the surface is released should vary from below the Halocline (500 meters deep, Fig. 4b) to around 1 km deep.

This will eventually remove the thin, less salty seawater layer from the top of the ocean and thus increase bottom-up the salinity of the Arctic surface seawater layer. This increase in salinity will increase the density of the superficial seawater and thus allow more water from the Atlantic to enter the Arctic Ocean surface. Such project would require an ice breaker ship with a pumping system attached to a pipelines at least 1 km deep and attached to the ocean bed, as shown in Fig. 8. The energy utilized to operate the pumps could be generated by offshore floating wind turbines or brought from Canada or Russia via underwater transmission lines.

Fig. 8
figure 8

Diagram of the Arctic Ocean mixer proposed in this paper

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The advantage of this approach is that the system always pumps the least salty water to the deep ocean. The water pumping from the surface attracts more of the less salty water from the surface close to the pumping inlet. This will continue until the salinity of the pumped water is similar to the salinity of the deep ocean layer. Thus, this solution could extinguish the halocline layer of the whole Arctic, with only one large ship. On the other hand, if high-salinity water was pumped onto the surface of the Arctic Ocean, it would sink due to its higher density and would not mix with the thin layer of superficial seawater.

The energy requirement for pumping the water from the surface to the bottom of the Arctic Ocean is calculated using Eq. 6.

$$E_{M} = F_{M} \times \left( {D_{d} - D_{s} } \right) \times d \times a$$
(6)

where \(E_{M}\) is the energy required to mix the superficial and deep Arctic Ocean waters (J). \(F_{M}\) is the average flow of superficial Arctic seawater to the deep Arctic Ocean (m3/s). \(D_{d}\) is the density of seawater at a depth of 1 km (1070.673 kg/m3). \(D_{s}\) is the density of seawater at the surface (1067.551 kg/m3). \(d\) is the pumping depth (1.000 m). \(a\) is the acceleration of gravity (9.81 m/s2).

A challenge of this alternative is that the water from the Pacific, which is considerable less salty than the water from the North Atlantic Ocean will flow through the Bering Strait and contribute to reducing the salinity of the Arctic ice. Thus, a partial restriction of the Bering Strait current with submerged floating barriers might be required [18, 19].

3 Results

This section intends to compare the proposed strategies to increase the salinity of the Arctic Ocean estimating the flows and salinity concentration mass balances, energy requirements and estimated costs. The assumptions made in this section intend to create a conservative estimate of future scenarios operating the different strategies to increase the salinity of the Arctic Ocean. In order to estimate the current flow and salinity concentration balances of the superficial Arctic Ocean, the values with reasonable estimates were taken from the literature and presented in Table 3 and the unknown flows were estimated using the mass balances Eqs. 2 and 4. Note that these are just preliminary scenarios with the intent of giving an overall idea of a possible outcome of implementing the proposed strategies to increase the salinity of the Arctic Ocean superficial seawater.

Table 3 Arctic Ocean superficial salinity mass balance
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After the salinity of the Arctic reaches a threshold of 32 g/l salinity, as proposed in Table 2, the Superficial North Atlantic current will move into the Arctic Ocean. This will thus increase the mixing of the superficial seawaters of the Arctic, and the salinity of the Arctic Ocean will considerably increase. At this point, the amount of energy required to reduce the salinity of the Arctic Ocean could then be reduced. However, the capital intensive river reverser systems continue operational due to its mutual benefits or also providing water to drought prone regions. It is also assumed that after the targeted salinity of the Arctic Ocean is reached, the rain patterns in the Arctic ocean will increase by 50% (due to the increase in temperature and upward wind pattern over the Arctic Ocean), the evaporation will increase by 150% (due to the melting of the Arctic sea ice cover), the melting of Greenland with barriers will increase 50%, and the river flows is reduced to half of their current flow.

The middle of the way scenario to reach the ultimate goal of 2 g/l increases in superficial Arctic Ocean salinity using Eqs. 2 and 4 and assuming an average North Atlantic Ocean current compared to the current flow and targeted flow, reduction in river flows to a half, reduction in Greenland melting by a half, increase in precipitation by 25% compared to current values, increase in evaporation by 50% result in a required pumping of superficial Arctic Ocean water to the deep Arctic Ocean of 5988 km3/year over 50 years. After these 50 years, the Arctic Ocean superficial salinity will reach the threshold in which the North Atlantic Ocean current can naturally enter the Arctic Ocean.

The energy requirement for operating the proposed strategies, as suggested in Table 3, is presented in Table 4. Equation 5 is applied to estimate the energy requirement for reversing the Canadian and Russian rivers, and Eq. 6 is applied to estimate the energy requirement for pumping the superficial Arctic Ocean seawater to the deep ocean. It can be seen that the estimated total energy requirement for operation of the proposed solutions is 116.5 GW for 50 years in which 99 is to reverse the USA, Canadian and Russian rivers, and 17.5 to pump water from the Arctic Ocean surface to the deep ocean. This is equivalent to around five Three Gorges Dam (generation capacity of 22.5 GW) operating at full capacity throughout the year.

Table 4 Comparison of strategies to reduce the input of freshwater to the Arctic Ocean
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4 Discussion

Given the numerous relevant impacts of the approaches to allow the North Atlantic current to reach the Arctic, these impacts are described in Table 5.

Table 5 Advantages, disadvantages and unknown impacts of strengthening the North Atlantic current
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Global warming could contribute in two ways to the dynamics in the Arctic Ocean. It increases the temperature of the North Atlantic Ocean, however, it also increases the melting of Greenland ice, which cools down the surface temperature of the North Atlantic current and reduces the salinity of the surface water of the Arctic Ocean [55]. In other words, global warming might not contribute to the North Atlantic Ocean to flow above the Arctic Ocean. At least until there is ice to be melted in Greenland.

5 Conclusion

This paper has shown that increasing the salinity of the surface water of the Arctic region would allow the North Atlantic Ocean to flow above the superficial Arctic layer, thus transporting heat from the Atlantic Ocean into the Arctic and increasing the amount of heat radiated into space and overall cooling the Earth’s oceans and possibly the Earth as a whole. The cooling of the oceans will happen from the bottom of the ocean until it reaches its surface. It might take hundreds or thousands of years for the effects of the cooling to the detected in the world’s atmosphere.

Three strategies were discussed to increase the salinity of the Arctic Ocean surface waters so that the North Atlantic current can flow above the Arctic Ocean. These strategies involve reducing the river flow to the Arctic, reducing Greenland ice sheet melting and mixing the Arctic Ocean waters. In other words, these alternatives would be convenient of the Arctic region, with the increase in temperature and convenient for the world as a whole due to the reduction in ocean temperatures. Regarding the energy requirements, the most attractive projects in a descending order are the Greenland submerged barriers, Arctic water mixing, Ob transposition, Mackenzie transposition, Yenisei transposition and Lena transposition. Regarding the investment costs, the most interesting projects in a descending order are the Arctic water mixing, Ob transposition, Mackenzie transposition, Yenisei transposition, Greenland submerged barriers and Lena transposition. It is estimated that after implementing the proposed solutions, it would take around 50 years to allow the North Atlantic Ocean current to flow above the Arctic Ocean.

Human intervention is already having serious impacts on the Earth’s climate, biosphere, land and oceans. Different proposals of how these impacts should be managed, and possible strategies to reduce these impacts are being considered to preserve life on Earth. This paper argues that comparing the advantages and disadvantages of allowing the North Atlantic current to enter the Arctic Ocean, this alternative should be further studied and considered for tackling global warming.