Underwater Radionuclides Heatwaves with 3-degrees Celsius Radioactivity Decay Dispersed and Spread fastest in North Pacific, and it flowing in Black Stream headed to US Coastal. Future – Everyday Marine Heatwaves is at hand

Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants.

Although environmental pollution can be caused by natural events, the word pollution generally implies that the contaminants have a human source, such as manufacturing, extractive industries, poor waste management, transportation or agriculture. Pollution is often classed as point source (coming from a highly concentrated specific site, such as a factory, mine, construction site), or nonpoint source pollution (coming from widespread distributed sources, such as microplastics or agricultural runoff).

The United Nations considers pollution to be the "presence of substances and heat in environmental media (air, water, land) whose nature, location, or quantity produces undesirable environmental effects."
 

Radioactive Decay from Radionuclides Emitted Heat Energy

Radioactive contamination is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirable. The International System of Units (SI) unit of radioactive activity is the becquerel (Bq). One Bq is defined as one transformation (or decay or disintegration) per second.

Such contamination presents a hazard because the radioactive decay of the contaminants produces ionizing radiation (namely alpha, beta, gamma rays and free neutrons). The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body. It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable. The effects of ionizing radiation are often measured in units of gray for mechanical or sievert for damage to tissue.

High levels of contamination may pose major risks to people and the environment. People can be exposed to potentially lethal radiation levels, both externally and internally, from the spread of contamination following an accident (or a deliberate initiation) involving large quantities of radioactive material.

Radionuclides are produced as an unavoidable result of nuclear fission and nuclear explosions. The process of nuclear fission creates a wide range of fission products, most of which are radionuclides. Further radionuclides are created from irradiation of the nuclear fuel (creating a range of actinides) and of the surrounding structures, yielding activation products. This complex mixture of radionuclides with different chemistries and radioactivity makes handling nuclear waste and dealing with nuclear fallout particularly problematic.

A radionuclide is a nuclide that is unstable and known to undergo radioactive decay into a different nuclide, which may be another radionuclide. Radiation emitted by radionuclides is almost always ionizing radiation because it is energetic enough to liberate an electron from another atom. Different isotopes emit different types and levels of radiation, which last for different periods of time. Radionuclides that find their way into the environment may cause harmful effects as radioactive contamination.

 
The Point Source of Radioactive Pollution in effect

The sources of radioactive pollution can be classified into two groups: natural and man-made. Following an atmospheric nuclear weapon discharge or a nuclear reactor containment breach, the air, soil, people, plants, water and animals in the vicinity will become contaminated by nuclear fuel and fission products. Cases of widespread radioactive contamination include the Bikini Atoll, the Rocky Flats Plant in Colorado, the area near the Fukushima Daiichi nuclear disaster, the area near the Chernobyl disaster, and the area near the Mayak disaster.

Many people have argued that an expansion of nuclear power would help combat climate change. A 2025 study found that each nuclear reactor closure in the United States between 1993 and 2022 increased state-level per-capita carbon emissions between 6% and 8%. Others have argued that it is one way to reduce emissions, but it comes with its own problems, such as risks related to severe nuclear accidents, attacks on nuclear sites, and nuclear terrorism. Some activists also believe that there are better ways of dealing with climate change than investing in nuclear power, including the improved energy efficiency and greater reliance on decentralized and renewable energy sources.

A release of radioactive materials followed the 2011 Japanese tsunami which damaged the Fukushima I Nuclear Power Plant, resulting in hydrogen gas explosions and partial meltdowns. The Fukushima disaster was classified a Level 7 event. The large-scale release of radioactivity resulted in people being evacuated from a 20 km exclusion zone set up around the power plant, similar to the 30 km radius Chernobyl Exclusion Zone still in effect.

In 2011, an earthquake and tsunami caused a loss of electric power at the Fukushima Daiichi nuclear power plant in Japan (via severing the connection to the external grid and destroying the backup diesel generators). The decay heat could not be removed, and the reactor cores of units 1, 2 and 3 overheated, the nuclear fuel melted, and the containments were breached. Radioactive materials were released from the plant to the atmosphere and to the ocean.

The nuclear power industry has improved the safety and performance of reactors, and has proposed new safer (but generally untested) reactor designs but there is no guarantee that the reactors will be designed, built and operated correctly. Mistakes do occur and the designers of reactors at Fukushima in Japan did not anticipate that a tsunami generated by an earthquake would disable the backup systems that were supposed to stabilize the reactor after the earthquake.

Scientists suspected that radioactive elements continued to leak into the ocean. High levels of caesium-134 were found in local fish, despite the isotope's comparatively shorter half-life. Meanwhile, radiation levels in the nearby sea water did not fall as expected.

The UNSCEAR report in 2020 determined "direct releases in the first three months amounting to about 10 to 20 PBq [petabecquerel, 10¹⁵ Bq] of iodine-131 and about 3 to 6 PBq of caesium-137". About 82 percent having flowed into the sea before 8 April 2011.

 
Ocean Temperature and its crucial role in Global Climate System

There are many effects of climate change on oceans. One of the most important is an increase in ocean temperatures. More frequent marine heatwaves are linked to this. The rising temperature contributes to a rise in sea levels due to the expansion of water as it warms and the melting of ice sheets on land. Other effects on oceans include sea ice decline, reducing pH values and oxygen levels, as well as increased ocean stratification. All this can lead to changes of ocean currents. Such currents transport massive amounts of water, gases, pollutants and heat to different parts of the world, and from the surface into the deep ocean, for example by moving contaminants from the surface into the deep ocean. All this has impacts on the global climate system.

The various layers of the oceans have different temperatures. For example, the water is colder towards the bottom of the ocean. This temperature stratification will increase as the ocean surface warms due to rising air temperatures. Connected to this is a decline in mixing of the ocean layers, so that warm water stabilizes near the surface. A reduction of cold, deep water circulation follows. The reduced vertical mixing makes it harder for the ocean to absorb heat. So a larger share of future warming goes into the atmosphere and land. One result is an increase in the amount of energy available for tropical cyclones and other storms. Another result is a decrease in nutrients for fish in the upper ocean layers.

The ocean temperature plays a crucial role in the global climate system, ocean currents and for marine habitats. It varies depending on depth, geographical location and season.

The ocean temperature also depends on the amount of solar radiation falling on its surface. In the tropics, with the Sun nearly overhead, the temperature of the surface layers can rise to over 30 °C (86 °F). Near the poles the temperature in equilibrium with the sea ice is about −2 °C (28 °F).

Ocean warming is projected to push the tropical Indian Ocean into a basin-wide near-permanent heatwave state by the end of the 21st century, where marine heatwaves are projected to increase from 20 days per year (1970–2000) to 220–250 days per year. Similarly, in the western North Pacific region, model projections show the mean duration of marine heatwave events rising from about 11 days (1982–2014) to about 138 days per event, and annual marine heatwave days rising to about 270 days by 2100 under high emissions.

A study published in 2025 projected that rising ocean temperatures, together with other climate-driven stressors, will more than double cumulative impacts on marine ecosystems by mid-century. It particularly affects in the Arctic, Antarctic, tropical regions, and coastal areas where biodiversity and human reliance are highest.

While marine heatwaves have mostly been studied at the sea surface, they can also occur at depth, including at the sea floor. It is clear that the oceans are warming as a result of climate change and this rate of warming is increasing. The upper ocean (above 700 m) is warming fastest, but the warming trend extends throughout the ocean. In 2022, the global ocean was the hottest ever recorded by humans.

Unlike heatwaves on land, marine heatwaves can extend over vast areas, persist for weeks to months to years, and extend to subsurface levels. Regional climate patterns including interdecadal oscillations like El Niño Southern Oscillation (ENSO) have also contributed to marine heatwave events such as "The Blob" in the Northeastern Pacific.

Repeated marine heatwaves in the Northeast Pacific led to dramatic changes in animal abundances, predator-prey relationships, and energy flux throughout the ecosystem. Marine heatwave events were expected to increased risk factors and health impacts affect coastal and inland communities as global average temperature and extreme heat events increase. These events had drastic and long-term impacts.

Investment and Adaptation in Thermal comfort can increase 11% people performance and productivity while facing the heat and high humidity. Global Heat Alert ahead

Thermal comfort is the condition of mind that expresses subjective satisfaction with the thermal environment. The human body can be viewed as a heat engine where food is the input energy. The human body will release excess heat into the environment, so the body can continue to operate. The heat transfer is proportional to temperature difference. In cold environments, the body loses more heat to the environment and in hot environments the body does not release enough heat. Both the hot and cold scenarios lead to discomfort.

The concept of thermal comfort is closely related to thermal stress. This attempts to predict the impact of solar radiation, air movement, and humidity for military personnel undergoing training exercises or athletes during competitive events. Several thermal stress indices have been proposed, such as the Predicted Heat Strain (PHS) or the humidex. Generally, humans do not perform well under thermal stress. People's performances under thermal stress are about 11% lower than their performance at normal thermal wet conditions. Also, human performance in relation to thermal stress varies greatly by the type of task which the individual is completing. Some of the physiological effects of thermal heat stress include increased blood flow to the skin, sweating, and increased ventilation.

Thermal comfort is influenced by factors like air temperature, mean radiant temperature, relative humidity, air speed, metabolic rate, and clothing. Thermal conditions can affect learning, cognitive performance, task completion, disease transmission, and sleep.

Psychological adaptation

Thermal comfort as a "condition of mind" is defined in psychological terms. Among the factors that affect the condition of mind (in the laboratory) are a sense of control over the temperature, knowledge of the temperature and the appearance of the (test) environment. A thermal test chamber that appeared residential "felt" warmer than one which looked like the inside of a refrigerator.

Physiological adaptation

The body has several thermal adjustment mechanisms to survive in drastic temperature environments. In a cold environment the body utilizes vasoconstriction; which reduces blood flow to the skin, skin temperature and heat dissipation. In a warm environment, vasodilation will increase blood flow to the skin, heat transport, and skin temperature and heat dissipation. If there is an imbalance despite the vasomotor adjustments listed above, in a warm environment sweat production will start and provide evaporative cooling. If this is insufficient, hyperthermia will set in, body temperature may reach 40 °C (104 °F), and heat stroke may occur. In a cold environment, shivering will start, involuntarily forcing the muscles to work and increasing the heat production by up to a factor of 10. If equilibrium is not restored, hypothermia can set in, which can be fatal. Long-term adjustments to extreme temperatures, of a few days to six months, may result in cardiovascular and endocrine adjustments. A hot climate may create increased blood volume, improving the effectiveness of vasodilation, enhanced performance of the sweat mechanism, and the readjustment of thermal preferences. In cold or underheated conditions, vasoconstriction can become permanent, resulting in decreased blood volume and increased body metabolic rate

Behavioral adaptation

In naturally ventilated buildings, occupants take numerous actions to keep themselves comfortable when the indoor conditions drift towards discomfort. Operating windows and fans, adjusting blinds/shades, changing clothing, and consuming food and drinks are some of the common adaptive strategies. Among these, adjusting windows is the most common. Those occupants who take these sorts of actions tend to feel cooler at warmer temperatures than those who do not.

Important of human physiological process to identify Hypothermia/Hyperthermia

The human body always works to remain in homeostasis. One form of homeostasis is thermoregulation. Body temperature varies in every individual, but the average internal temperature is 37.0 °C (98.6 °F). Sufficient stress from extreme external temperature may cause injury or death if it exceeds the ability of the body to thermoregulate. Hypothermia can set in when the core temperature drops to 35 °C (95 °F). Hyperthermia can set in when the core body temperature rises above 37.5–38.3 °C (99.5–100.9 °F). Humans have adapted to living in climates where hypothermia and hyperthermia were common primarily through culture and technology, such as the use of clothing and shelter.

Satisfaction with the thermal environment is important because thermal conditions are potentially life-threatening for humans if the core body temperature reaches conditions of hyperthermia or hypothermia. Buildings modify the conditions of the external environment and reduce the effort that the human body needs to do in order to stay stable at a normal human body temperature, important for the correct functioning of human physiological processes.

In building science studies, thermal comfort has been related to productivity and health. Office workers who are satisfied with their thermal environment are more productive. The combination of high temperature and high relative humidity reduces thermal comfort and indoor air quality.

Indoor spaces that are not air conditioned can create indoor heat waves if the outside air cools but the thermal mass of the building traps the hotter air inside. Cedeño-Laurent et al. believe these may become worse as climate change increases the "frequency, duration, and intensity of heat waves" and will be harder to adjust to in areas that are designed for colder climate.

Mortality due to heat waves could be reduced if buildings were better designed to modify the internal climate, or if the occupants were better educated about the issues, so they can take action on time. Heatwave early warning and response systems are important elements of heat action plans.

Heat illness in rising temperatures

Since the 1970s, temperature on the surface of Earth has become warmer each decade. This increase happened faster than in any other 50-year period over at least the last 2000 years. Compared to the second half of the 19th century, temperature in the 21st century show a warming of 1.09 °C.

Extreme heat is a direct threat to health, especially for people over 65 years, children, people living in cities and those who have already existing health conditions. Rising global temperatures impact the health and well-being of people in multiple ways. In the last few decades, people all over the world have become more vulnerable to heat and experienced an increasing number of life-threatening heatwave events. Extreme heat has negative effects on mental health as well, raising the risk of mental health-related hospitalizations and suicidal.

People with cognitive health issues (e.g. depression, dementia, Parkinson's disease) are more at risk when faced with high temperatures and ought to be extra careful as cognitive performance has been shown to be differentially affected by heat. People with diabetes and those who are overweight, have sleep deprivation, or have cardiovascular/cerebrovascular conditions should avoid too much heat exposure.

Although heat itself is not a direct threat to health on its own, a combination of factors of rising temperatures can detriment one's health. The effects of heat on an individual's health is influenced by temperatures, humidity, exercise, hydration, age, pre-existing health status and also by occupation, clothing, behavior, autonomy, vulnerability, and sense of obligation.

Physical exercise is beneficial for reducing the risk the many illnesses and for mental health. At the same time the number of hours per day when the temperature is dangerously high for outdoor exercise has been increasing. The rising heat also impacts people's ability to work and the number of hours when it is not safe to work outdoors (construction, agriculture, etc.) has also increased.

There are two types of heat the body is adapted to, humid heat and dry heat, but the body adapts to both in similar ways. Humid heat is characterized by warmer temperatures with a high amount of water vapor in the air, while dry heat is characterized by warmer temperatures with little to no vapor, such as desert conditions. With humid heat, the moisture in the air can prevent the evaporation of sweat. Regardless of acclimatization, humid heat poses a far greater threat than dry heat; humans cannot carry out physical outdoor activities at any temperature above 32 °C (90 °F) when the ambient humidity is greater than 95%. When combined with this high humidity, the theoretical limit to human survival in the shade, even with unlimited water, is 35 °C (95 °F) – theoretically equivalent to a heat index of 70 °C (158 °F) Dry heat, on the other hand, can cause dehydration, as sweat will tend to evaporate extremely quickly. Individuals with less fat and slightly lower body temperatures can more easily handle both humid and dry heat.

Heat stress causes illness but also may account for an increase in workplace accidents, and a decrease in worker productivity. Worker injuries attributable to heat include those caused by: sweaty palms, fogged-up safety glasses, and dizziness. Burns may also occur as a result of accidental contact with hot surfaces or steam. In the United States, occupational heat stress is becoming more significant as the average temperatures increase but remains overlooked. There are few studies and regulations regarding heat exposure of workers.

In unusually hot conditions, all workers should be aware of their risk for heat illness and should ensure that they drink plenty of water and take breaks in cool places to avoid any severe impacts.

Continued Global Heating can Supercharge High Humidity to exceed 100% Supersaturated - in Dew point scale. Find your comfort temperature with 60% humid to comfort indoor and outdoor

Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present.

Humidity depends on the temperature and pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 8 g of water per cubic metre of air at 8 °C (46 °F), and 28 g of water per cubic metre of air at 30 °C (86 °F).

The dew point depends on how much water vapor the air contains. If the air is very dry and has few water molecules, the dew point is low and surfaces must be much cooler than the air for condensation to occur. If the air is very humid and contains many water molecules, the dew point is high and condensation can occur on surfaces that are only a few degrees cooler than the air.

Humid air is less dense than dry air because a molecule of water (m ≈ 18 Da) is less massive than either a molecule of nitrogen (m ≈ 28) or a molecule of oxygen (m ≈ 32). About 78% of the molecules in dry air are nitrogen (N2). Another 21% of the molecules in dry air are oxygen (O2). The final 1% of dry air is a mixture of other gases. 

Relative humidity is an important metric to expressed humid 

 
Relative humidity varies with any change in the temperature or pressure of the air: colder air can contain less vapour, and water will tend to condense out of the air more at lower temperatures. So changing the temperature of air can change the relative humidity, even when the specific humidity remains constant. If two parcels of air have the same specific humidity and temperature but different pressures, the parcel at the higher pressure will have the higher relative humidity.

Cooling air increases the relative humidity. If the relative humidity rises to 100% (the dew point) and there is an available surface or particle, the water vapour will condense into liquid or deposit into ice. Likewise, warming air decreases the relative humidity. Warming some air containing a fog may cause that fog to evaporate, as the droplets are prone to total evaporation due to the lowering partial pressure of water vapour in that air, as the temperature rises.

Relative humidity only considers the invisible water vapour. Mists, clouds, fogs and aerosols of water do not count towards the measure of relative humidity of the air, although their presence is an indication that a body of air may be close to the dew point.

Relative humidity is normally expressed as a percentage; a higher percentage means that the air–water mixture is more humid. At 100% relative humidity, the air is saturated and is at its dew point. In the absence of a foreign body on which droplets or crystals can nucleate, the relative humidity can exceed 100%, in which case the air is said to be supersaturated. Introduction of some particles or a surface to a body of air above 100% relative humidity will allow condensation or ice to form on those nuclei, thereby removing some of the vapour and lowering the humidity.

Relative humidity is an important metric used in weather forecasts and reports, as it is an indicator of the likelihood of precipitation, dew, or fog. In hot summer weather, a rise in relative humidity increases the apparent temperature to humans (and other animals) by hindering the evaporation of perspiration from the skin. For example, according to the heat index, a relative humidity of 75% at air temperature of 80.0 °F (26.7 °C) would feel like 83.6 ± 1.3 °F (28.7 ± 0.7 °C).

When the temperature is high and the relative humidity is low, evaporation of water is rapid; soil dries, wet clothes hung on a line or rack dry quickly, and perspiration readily evaporates from the skin.

High/Extreme Humidity in Climate variable across the globe

While humidity itself is a climate variable, it also affects other climate variables. Environmental humidity is affected by winds and by rainfall.

The most humid cities on Earth are generally located closer to the equator, near coastal regions. Cities in parts of Asia and Oceania are among the most humid. Bangkok, Ho Chi Minh City, Kuala Lumpur, Hong Kong, Manila, Jakarta, Naha, Singapore, Kaohsiung and Taipei have very high humidity most or all year round because of their proximity to water bodies and the equator and often overcast weather. 

Some places experience extreme humidity during their rainy seasons combined with warmth giving the feel of a lukewarm sauna, such as Kolkata, Chennai and Kochi in India, and Lahore in Pakistan. Sukkur city located on the Indus River in Pakistan has some of the highest and most uncomfortable dew points in the country, frequently exceeding 30 °C (86 °F) in the monsoon season.

High temperatures combine with the high dew point to create heat index in excess of 65 °C (149 °F). Darwin experiences an extremely humid wet season from December to April. Houston, Miami, San Diego, Osaka, Shanghai, Shenzhen and Tokyo also have an extreme humid period in their summer months. During the South-west and North-east Monsoon seasons (respectively, late May to September and November to March), expect heavy rains and a relatively high humidity post-rainfall. 

Outside the monsoon seasons, humidity is high (in comparison to countries further from the Equator), but completely sunny days abound. In cooler places such as Northern Tasmania, Australia, high humidity is experienced all year due to the ocean between mainland Australia and Tasmania. In the summer the hot dry air is absorbed by this ocean and the temperature rarely climbs above 35 °C (95 °F).

Human comfort in high humidity

Humans are sensitive to humid air because the human body uses evaporative cooling as the primary mechanism to regulate temperature. Under humid conditions, the rate at which perspiration evaporates on the skin is lower than it would be under arid conditions. Because humans perceive the rate of heat transfer from the body rather than temperature itself, we feel warmer when the relative humidity is high than when it is low. 

Humans can be comfortable within a wide range of humidities depending on the temperature—from 30 to 70%—but ideally not above the Absolute (60 °F Dew Point), between 40% and 60%. In general, higher temperatures will require lower humidities to achieve thermal comfort compared to lower temperatures, with all other factors held constant. For example, with clothing level = 1, metabolic rate = 1.1, and air speed 0.1 m/s, a change in air temperature and mean radiant temperature from 20 °C to 24 °C would lower the maximum acceptable relative humidity from 100% to 65% to maintain thermal comfort conditions.

The human body dissipates heat through perspiration and its evaporation. Heat convection, to the surrounding air, and thermal radiation are the primary modes of heat transport from the body. Under conditions of high humidity, the rate of evaporation of sweat from the skin decreases. Also, if the atmosphere is as warm or warmer than the skin during times of high humidity, blood brought to the body surface cannot dissipate heat by conduction to the air. With so much blood going to the external surface of the body, less goes to the active muscles, the brain, and other internal organs. Physical strength declines, and fatigue occurs sooner than it would otherwise. Alertness and mental capacity also may be affected, resulting in heat stroke or hyperthermia. High temperatures pose serious stresses for the human body, placing it in great danger of injury or even death.

Very low humidity can create discomfort, respiratory problems, and aggravate allergies in some individuals. Low humidity causes tissue lining nasal passages to dry, crack and become more susceptible to penetration of rhinovirus cold viruses. Extremely low (below 20 %) relative humidities may also cause eye irritation. Indoor relative humidities kept above 30% reduce the likelihood of the occupant's nasal passages drying out, especially in winter.

Wet-bulb temperature and health

Living organisms can survive only within a certain temperature range. When the ambient temperature is excessive, many animals cool themselves to below ambient temperature by evaporative cooling (sweat in humans and horses, saliva and water in dogs and other mammals); this helps to prevent potentially fatal hyperthermia due to heat stress. The effectiveness of evaporative cooling depends upon humidity; wet-bulb temperature, or more complex calculated quantities such as wet-bulb globe temperature (WBGT) which also takes account of solar radiation, give a useful indication of the degree of heat stress, and are used by several agencies as the basis for heat stress prevention guidelines.

Given the body's vital requirement to maintain a core temperature of approximately 37°C, a sustained wet-bulb temperature exceeding 35 °C (95 °F) —equivalent to a heat index of 71 °C (160 °F)— is likely to be fatal even to fit and healthy people, semi-nude in the shade and next to a fan; at this temperature human bodies switch from shedding heat to the environment, to gaining heat from it. A 2022 study found that the critical wet-bulb temperature at which heat stress can no longer be compensated in young, healthy adults mimicking basic activities of daily life strongly depended on the ambient temperature and humidity conditions, but was 5–10°C below the theoretical limit.

A 2015 study concluded that depending on the extent of future global warming, parts of the world could become uninhabitable due to deadly wet-bulb temperatures. A 2020 study reported cases where a 35 °C (95 °F) wet-bulb temperature had already occurred, albeit too briefly and in too small a locality to cause fatalities. Severe mortality and morbidity impacts can occur at much lower wet-bulb temperatures due to suboptimal physiological and behavioral conditions.

Climate change feedbacks

These feedback processes alter the pace of global warming. For instance, warmer air can hold more moisture in the form of water vapour, which is itself a potent greenhouse gas. Warmer air can also make clouds higher and thinner, and therefore more insulating, increasing climate warming.

Global sea level is rising as a consequence of thermal expansion and the melting of glaciers and ice sheets. Sea level rise has increased over time, reaching 4.8 cm per decade between 2014 and 2023.

Climate change has led to decades of shrinking and thinning of the Arctic sea ice. While ice-free summers are expected to be rare at 1.5 °C degrees of warming, they are set to occur once every three to ten years at a warming level of 2 °C.

Different regions of the world warm at different rates. The pattern is independent of where greenhouse gases are emitted, because the gases persist long enough to diffuse across the planet. Since the pre-industrial period, the average surface temperature over land regions has increased almost twice as fast as the global average surface temperature. This is because oceans lose more heat by evaporation and oceans can store a lot of heat. The thermal energy in the global climate system has grown with only brief pauses since at least 1970, and over 90% of this extra energy has been stored in the ocean. The rest has heated the atmosphere, melted ice, and warmed the continents. At the same time, warming also causes greater evaporation from the oceans, leading to more atmospheric humidity, more and heavier precipitation.

Pacific Ocean Warming increased at an accelerating rate, heated with so much zettajoule. Heat Content in ocean change it current Climate Change phenomenon trends

The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on the definition, to Antarctica) in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east.

At 165,250,000 square kilometers (63,800,000 square miles) in area (as defined with a southern Antarctic border), the largest division of the World Ocean and the hydrosphere covers about 46% of Earth's water surface and about 32% of the planet's total surface area, larger than its entire land area (148,000,000 km² (57,000,000 sq mi)). The centers of both the water hemisphere and the Western Hemisphere, as well as the oceanic pole of inaccessibility, are in the Pacific Ocean.

The Pacific Ocean's mean depth is 4,000 meters (13,000 feet). The Challenger Deep in the Mariana Trench, located in the northwestern Pacific, is the deepest known point in the world, reaching a depth of 10,928 meters (35,853 feet). The Pacific also contains the deepest point in the Southern Hemisphere, the Horizon Deep in the Tonga Trench, at 10,823 meters (35,509 feet). The third deepest point on Earth, the Sirena Deep, is also located in the Mariana Trench.

Due to the effects of plate tectonics, the Pacific Ocean is currently shrinking by roughly 2.5 cm (1 in) per year on three sides, roughly averaging 0.52 km² (0.20 sq mi) a year. By contrast, the Atlantic Ocean is increasing in size.

Along the Pacific Ocean's irregular western margins lie many seas, the largest of which are the Celebes Sea, Coral Sea, East China Sea (East Sea), Philippine Sea, Sea of Japan, South China Sea (South Sea), Sulu Sea, Tasman Sea, and Yellow Sea (West Sea of Korea). The Indonesian Seaway (including the Strait of Malacca and Torres Strait) joins the Pacific and the Indian Ocean to the west, and Drake Passage and the Strait of Magellan link the Pacific with the Atlantic Ocean on the east. To the north, the Bering Strait connects the Pacific with the Arctic Ocean.

The Pacific Ocean has most of the islands in the world. There are about 25,000 islands in the Pacific Ocean. Many tropical storms batter the islands of the Pacific. The lands around the Pacific Rim are full of volcanoes and often affected by earthquakes. Unknown Tsunamis, caused by underwater earthquakes, have devastated many islands and in some cases destroyed entire towns.

Pacific Oceans and Heat Uptake

Ocean heat content (OHC) or ocean heat uptake (OHU) is the energy absorbed and stored by oceans. To calculate the ocean heat content, it is necessary to measure ocean temperature at many different locations and depths. The North Pacific, North Atlantic, the Mediterranean, and the Southern Ocean all recorded their highest heat observations for more than sixty years of global measurements.

Numerous independent studies in recent years have found a multi-decadal rise in OHC of upper ocean regions that has begun to penetrate to deeper regions. The upper ocean (0–700 m) has warmed since 1971, while it is very likely that warming has occurred at intermediate depths (700–2000 m) and likely that deep ocean (below 2000 m) temperatures have increased. There is very high confidence that increased ocean heat content in response to anthropogenic carbon dioxide emissions and waste pollution is essentially irreversible on human time scales.

In 2021 scientists from around the world revealed that, per their measurement, the world oceans are hotter than ever recorded for the sixth straight year. “One way to think about this is the oceans have absorbed heat equivalent to seven Hiroshima atomic bombs detonating each second, 24 hours a day, 365 days a year.” Scientifically, the data shows that the oceans heated up by about 14 zettajoules.

In 2023, the world's oceans were again the hottest in the historical record and exceeded the previous 2022 record maximum. The five highest ocean heat observations to a depth of 2000 meters occurred in the period 2019–2023.

With improving observation in recent decades, the heat content of the upper ocean has been analyzed to have increased at an accelerating rate. Changes in ocean temperature greatly affect ecosystems in oceans and on land.

Ocean heat uptake accounts for over 90% of total planetary heat uptake, mainly as a consequence of human-caused changes to the composition of Earth's atmosphere.

Concentrated releases in association with high sea surface temperatures help drive tropical cyclones, atmospheric rivers, atmospheric heat waves and other extreme weather events that can penetrate far inland. Altogether these processes enable the ocean to be Earth's largest thermal reservoir which functions to regulate the planet's climate; acting as both a sink and a source of energy. 

Current trends phenomenon of Climate Change

Marine Heatwave
A marine heatwave is a period of abnormally high sea surface temperatures compared to the typical temperatures in the past for a particular season and region. Unlike heatwaves on land, marine heatwaves can extend over vast areas, persist for weeks to months or even years, and occur at subsurface levels. It is clear that the ocean is warming as a result of climate change, and this rate of warming is increasing.

Scientists predict that the frequency, duration, scale (or area) and intensity of marine heatwaves will continue to increase. This is because sea surface temperatures will continue to increase with global warming, and therefore the frequency and intensity of marine heatwaves will also increase. Simply put, the more greenhouse gas emissions and waste pollution (or the less mitigation), the more the sea surface temperature will rise.

Many species already experience these temperature shifts during the course of marine heatwave events. There are many increased risk factors and health impacts to coastal and inland communities as global average temperature and extreme heat events increase.

The Blob

The Blob is a large mass of relatively warm water in the Pacific Ocean off the coast of North America that was first detected in late 2013 and continued to spread throughout 2014 and 2015. It is an example of a marine heatwave. Sea surface temperatures indicated that the Blob persisted into 2016, but it was initially thought to have dissipated later that year.

By September 2016, the Blob resurfaced and made itself known to meteorologists. The warm water mass was unusual for open ocean conditions and was considered to have played a role in the formation of the unusual weather conditions experienced along the Pacific coast of North America during the same time period. The warm waters of the Blob were nutrient-poor and adversely affected marine life.

In 2019 another scare was caused by a weaker form of the effect referred as "The Blob 2.0" and in 2021 the appearance of "The Southern Blob" at south of the equator near New Zealand has caused a major effect in South America, particularly Chile and Argentina.

The Blob was first detected in October 2013 and early 2014 by Nicholas Bond and his colleagues at the Joint Institute for the Study of the Atmosphere and Ocean of the University of Washington. It was detected when a large circular body of seawater did not cool as expected and remained much warmer than the average normal temperatures for that location and season.

Initially the Blob was reported as being 500 miles (800 km) wide and 300 feet (91 m) deep. It later expanded and reached a size of 1,000 miles (1,600 km) long, 1,000 miles (1,600 km) wide, and 300 feet (91 m) deep in. In February 2014, the temperature of the Blob was around 2.5 °C (4.5 °F) warmer than what was usual for the time of year. A NOAA scientist noted in September 2014 that, based on ocean temperature records, the North Pacific Ocean had not previously experienced temperatures so warm since climatologists began taking measurements.

In 2015 the atmospheric ridge causing the Blob finally disappeared. The Blob vanished shortly after in 2016. However, in its wake are many species that will take a long time to recover. Although the Blob is gone for now, scientists predict that similar marine heat waves are becoming more common due to the Earth's warming climate. Residual heat from the first blob in addition to warmer temperatures in 2019 lead to a second Blob scare. However, it was quelled by a series of storms that cooled the rising temperatures.

The reason for the phenomenon remains unclear, but it is speculated to partially be human caused climate change.

Caused by increased heat in Pacific Ocean

Environment

The Northwestern Pacific Ocean is most susceptible to micro plastic pollution due to its proximity to highly populated countries like Japan and China. The quantity of small plastic fragments floating in the north-east Pacific Ocean increased a hundredfold between 1972 and 2012. The ever-growing Great Pacific Garbage Patch between California and Japan is three times the size of France. An estimated 80,000 metric tons of plastic inhabit the patch, totaling 1.8 trillion pieces.

Marine pollution is a generic term for the harmful entry into the ocean of chemicals or particles. The main culprits are those using the rivers for disposing of their waste. The rivers then empty into the ocean, often also bringing chemicals used as fertilizers in agriculture. The excess of oxygen-depleting chemicals in the water leads to hypoxia and the creation of a dead zone.

Marine debris, also known as marine litter, is human-created waste that has ended up floating in a lake, sea, ocean, or waterway. Oceanic debris tends to accumulate at the center of gyres and coastlines, frequently washing aground where it is known as beach litter.

In addition, the Pacific Ocean has served as the crash site of satellites, including Mars 96, Fobos-Grunt, and Upper Atmosphere Research Satellite.

Nuclear waste

From 1946 to 1958, Marshall Islands served as the Pacific Proving Grounds, designated by the United States, and played host to a total of 67 nuclear tests conducted across various atolls. Several nuclear weapons were lost in the Pacific Ocean, including one-megaton bomb that was lost during the 1965 Philippine Sea A-4 incident.

In 2021, the discharge of radioactive water from the Fukushima nuclear plant into the Pacific Ocean over a course of 30 years was approved by the Japanese Cabinet. The Cabinet concluded the radioactive water would have been diluted to drinkable standard. Apart from dumping, leakage of tritium into the Pacific was estimated to be between 20 and 40 trillion Bqs from 2011 to 2013, according to the Fukushima plant.

Deep sea mining

An emerging threat for the Pacific Ocean is the development of deep-sea mining. Deep-sea mining is aimed at extracting manganese nodules that contain minerals such as magnesium, nickel, copper, zinc and cobalt. The largest deposits of these are found in the Pacific Ocean between Mexico and Hawaii in the Clarion Clipperton fracture zone.

Deep-sea mining for manganese nodules appears to have drastic consequences for the ocean. It disrupts deep-sea ecosystems and may cause irreversible damage to fragile marine habitats. Sediment stirring and chemical pollution threaten various marine animals. In addition, the mining process can lead to greenhouse gas emissions and promote further climate change. Preventing deep-sea mining is therefore important to ensure the long-term health of the ocean.

Options for reducing impacts

To address the root cause of more frequent and more intense marine heatwaves, climate change mitigation methods are needed to curb the increase in global temperature and in ocean temperatures.

Better forecasts of marine heatwaves and improved monitoring can also help to reduce impacts of these heatwaves.