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.