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Its chemical formula is CH4·8H2O; \"flammable ice\" is a clean new energy source for the future. Its main components are methane molecules and water molecules. Its formation is similar to, and closely related to, the formation process of oil and natural gas on the seabed. Large amounts of organic matter buried deep in marine strata, in an oxygen-free environment, are broken down by anaerobic bacteria, eventually forming oil and natural gas (gas oil). Much of this natural gas is then enclosed within water molecules, forming \"flammable ice\" under the low temperatures and high pressures at the seafloor. This is because natural gas has a special property: it can crystallize together with water at temperatures between 2 and 5 degrees Celsius, and this crystal is known as \"flammable ice\". Since its main component is methane, it is also often referred to as “methane hydrate”. Under normal temperature and pressure, it decomposes into water and methane; “flammable ice” can be considered as highly compressed solid natural gas. “Methane hydrate appears to be ice on the surface, but at the microscopic level its molecular structure consists of various \"cages\"; each cage is formed by several water molecules, with one gas molecule \"trapped\" inside each cage. Currently, methane clathrates are mainly found in the East and West Pacific Oceans as well as on the western edges of the Atlantic Ocean. They represent a new energy source with great potential for development; however, due to the difficulties involved in extracting them, methane clathrates remain intact in the seabed and permafrost to this day. 【The discovery of combustible ice】 As early as 1778, the British chemist Priestley began to study the temperature and pressure of gas hydrates that produce gases. In 1934, icy solid blockages were discovered in oil and gas pipelines as well as processing equipment; these solids were either ice or what is now known as combustible ice. In 1965, Soviet scientists predicted that natural gas hydrates might exist in the upper layers of the ocean floor, and later large quantities of combustible ice were finally discovered for the first time on the seabed of the Arctic. 【Formation and Storage】 Methane hydrates are formed as a result of oceanic plate activity. When oceanic plates sink, the older seafloor crust descends into the interior of the Earth, and oil and gas from the seabed rise to the surface along the edges of the plates. When exposed to cold seawater and under deep-sea pressure, natural gas reacts chemically with seawater to form hydrates. Scientists estimate that the distribution of seabed methane clathrates covers about 10% of the total ocean area, which is equivalent to 40 million square kilometers. It represents the most valuable mineral resource found on the seabed to date, and its reserves would be sufficient for human use for 1,000 years. “The formation of \"flammable ice\" requires three basic conditions: first, the temperature must not be too high; it can form above zero degrees, with 0–10°C being the optimal range, and the maximum limit is around 20°C, beyond which it decomposes. The second pressure must be sufficient, but it cannot be too high; at zero degrees, it can form when the pressure is above 30 atmospheres. Third, there must be a gas source underground. Because, on land, only the permafrost in Siberia possesses the conditions necessary to maintain a solid state, while the sediments at depths of 300–500 meters in the ocean may also have such low-temperature and high-pressure conditions. Therefore, the land-to-sea ratio of its distribution is 1:100. Not all areas with natural gas have \"flammable ice,\" because in addition to pressure, low temperature is also a key factor for the formation of such ice; therefore it is commonly found in permafrost regions. For a long time, it has been believed that due to the low latitude of our country’s maritime areas, it is impossible for \"flammable ice\" to exist there” ； In fact, both the East China Sea and the South China Sea in our country have the conditions for their formation. Beneath the East China Sea lies the East China Sea Basin, which covers an area of 250,000 square kilometers. After 20 years of exploration, the basin has yielded proven and controlled natural gas reserves of 148.4 billion cubic meters. Subsequently, a research team led by Jin Xianglong, an academician of the Chinese Academy of Engineering and an expert in oceanography, identified the temperature and pressure ranges in which methane clathrates can exist in the East China Sea, based on the necessary conditions for their formation. By taking into account the geothermal gradient as well as the geological conditions of the East China Sea, they determined the areas where methane clathrates are likely to be found, calculated the thickness of their stable zones, and conducted a preliminary assessment of the resource volume, concluding that the reserves are quite substantial. This opens up broader prospects for the surrounding areas to utilize efficient new energy sources in the new century. 【Storage and Prospects】 1 cubic meter of combustible ice can be converted into 164 cubic meters of natural gas and 0.8 cubic meters of water. Scientists estimate that the area covered by seabed methane clathrates is about 40 million square kilometers, accounting for 10% of the total ocean area. The reserves of seabed methane clathrates are sufficient to meet human needs for 1,000 years. As research and survey efforts progressed, the number of combustible ice deposits discovered in the world’s oceans increased gradually; 57 such deposits were found on the seabed in 1993, and this figure rose to 88 by 2001. According to estimates, the Black Sea Ridge off the southeastern coast of the United States contains as much as 18 billion tons of methane hydrate resources, enough to meet the country’s natural gas consumption needs for 105 years ； The combustible ice resources in the Sea of Japan and its surrounding areas can supply Japan for over 100 years. According to experts, the total global oil reserves range from 270 billion tons to 650 billion tons. At the current rate of consumption, oil resources worldwide will be exhausted in another 50–60 years. The discovery of combustible ice has brought new hope to humanity, which is facing an energy crisis. 【Joint Survey】 On June 2 this year, 26 Chinese and German scientists boarded the German research vessel \"Sonne\" to embark on a 42-day comprehensive geological survey of the South China Sea. Through seabed television observations and grab sampling via seabed television monitoring, giant carbonate rocks covering an area of approximately 430 square kilometers were discovered for the first time. Chinese and German scientists unanimously recommended naming the most typical structural feature in this natural carbonate rock area as the “Jiulong Methane Reef”. Among them, the character “dragon” represents China, while “nine” signifies the collaboration among multiple research groups. Isotopic dating analysis indicates that the carbonate crusts in the “Kowloon Methane Seep” area first formed around 45,000 years ago, and they continue to release methane gas to this day. Huang Yongyang, China’s first scientist of this field and chief engineer at the Guangzhou Marine Geology Survey Bureau, was extremely excited about this. He said that the evidence from surveys shows that the reserves of methane hydrates in the northern part of the South China Sea alone amount to roughly half of China’s total onshore oil reserves ； In addition, in the Xisha Trough, an area of 5,242 square kilometers where methane hydrates are present has been preliminarily identified, with estimated resources amounting to 4.1 trillion cubic meters. Since 1993, our country has been a pure oil importer, and it is estimated that the net oil import volume will rise to about 100 million tons by 2010, and to around 200 million tons by 2020. Therefore, understanding the status of methane clathrates and developing these resources holds great strategic significance for China’s future energy supply and sustainable economic development. Huang Yongyang said that over the next decade, China will invest 810 million yuan in investigating the resources of this new energy source. It is expected that by around 2008, an accurate assessment of the reserves of methane clathrates will be available, with trial extraction of these resources to begin in 2015. 【A Double-Edged Sword】 A \"double-edged sword\" shaped by both strategic advantages and risks. To date, at least 30 countries and regions around the world are conducting research, investigations, and exploration on combustible ice. In 1960, the former Soviet Union discovered its first natural gas hydrate reservoir in Siberia, and development began in 1969. Over 14 years of extraction, a total of 5.017 billion cubic meters of gas were harvested. The United States began conducting surveys on combustible ice in 1969. In 1998, methane clathrate was included as a **strategic energy resource for development** in long-term plans, with the goal of carrying out commercial pilot extraction by 2015. Japan began to pay attention to methane clathrates in 1992. To date, surveys and evaluations of methane clathrates in the surrounding seas have been largely completed; 7 exploration wells have been drilled, 12 mineralization areas have been identified, and methane clathrate samples have been successfully obtained. Its goal is to carry out commercial trial mining by 2010. However, humans still face many new challenges in extracting combustible ice buried in the deep sea. Some scholars believe that methane plays a role 10 to 20 times greater than carbon dioxide in causing global warming. Even the slightest damage to methane clathrate deposits can lead to a massive release of methane gas. Furthermore, extracting combustible ice from continental shelf seas is extremely difficult, and in the event of a blowout, it can cause disasters such as tsunamis, seabed landslides, and water pollution. It can be seen that, while serving as a new energy source in the future, combustible ice is also a dangerous one. The development and utilization of combustible ice is like a \"double-edged sword\" that requires careful handling. “\"Methane hydrate\" is ice containing methane, buried deep under the sea floor. It is due to the high pressure and low temperature conditions in the deep sea that water molecules bond tightly together through hydrogen bonds to form a three-dimensional network, which can trap gas molecules such as methane produced by the decomposition of ancient biological remains on the seabed, thereby forming hydrate methane. These hydrated methane molecules resemble pale gray ice balls, which is why they are called combustible ice. Once these ice balls rise from the seabed to the surface, they explode instantly. Methane hydrate is a potential energy source with large reserves. According to estimates by the International Geological Exploration Organization, the reserves of hydrated methane in the Earth’s deep seas are sufficient to exceed 2.84×1021 m3, which is 1,000 times the amount stored in conventional gas resources. Moreover, there may be 1.135×1020 m3 of gas hidden beneath these methane clathrate layers. Some experts believe that once hydrated methane is extracted, it will extend humanity’s history of fuel use by several centuries. To develop this new energy source, an international joint organization for deep-sea geological sampling research was established, involving 19 countries; 50 scientists and technicians set out from the East Coast of the United States aboard a ship equipped with advanced experimental facilities to explore hydrocarbons in the seabed. The 7 decks of this ship dedicated to methane hydrate exploration are equipped with advanced experimental equipment; it is the only ship in the world today capable of taking samples from rocks at great depths. The ship is fitted with equipment for studying sedimentology, paleoanthropology, petrology, geochemistry, geophysics, and other fields. This specialized ship is overseen by A&M University in Texas, with financial support provided by scientific foundations in the UK, Germany, France, Japan, Australia, the United States, and the European Union Science Foundation. The presence of combustible ice on the seabed can likely destabilize the ocean floor, often leading to large-scale seabed slumps that cause severe damage to underwater pipelines and communication cables. Worse still, if the seafloor strata fracture during an earthquake, gases released from the decomposition of free gas and hydrated methane will burst to the surface of the sea, or many highly concentrated flammable bubbles will form in the surface waters and above them. This not only poses a danger to ships passing by but also brings peril to aircraft flying at low altitudes. Some scholars believe that the many mysterious disappearances of ships and aircraft that have occurred over the waters of the Bermuda Triangle, located between Florida, the Bermuda Islands, and Puerto Rico, over the past few centuries – namely the so-called Bermuda mystery – may be related to this. Since combustible ice is formed under low temperature and high pressure in the deep sea, and hydrogen bonds are weak forces, the ice-like hydrated methane will automatically melt and decompose into gases as soon as it reaches the surface; therefore, there is no need to go to any trouble to decompose the hydrated methane – we simply need to use specialized equipment to collect these gases for use. It is worth noting that, although combustible ice holds promise as a new source of energy, methane is a potent greenhouse gas. If combustible ice is extracted using improper methods, the methane released into the atmosphere will exacerbate the greenhouse effect on Earth, leading to the melting of permafrost and polar ice caps and thus global warming. To develop methane clathrates safely and reasonably, environmental protection must be taken into account simultaneously. 【Extraction and Utilization of Methane Hydrates】 Methane hydrates are expected to replace coal, oil, and natural gas as a new energy source in the 21st century. Scientists estimate that the distribution of seabed methane clathrates covers about 10% of the total ocean area, which is equivalent to 40 million square kilometers. It represents the most valuable mineral resource found on the seabed to date, and its reserves would be sufficient for human use for 1,000 years. However, in the complex process of extracting combustible ice, any mistake can lead to severe environmental disasters, turning it into an enemy of environmental protection. First of all, it is very difficult to collect gases from seawater; combustible ice is distributed over large areas, and the methane released from it struggles to be gathered in one specific location. Moreover, once it leaves the seabed, it decomposes rapidly, increasing the risk of blowout accidents. More importantly, methane has a greenhouse effect 10 to 20 times stronger than that of carbon dioxide; if mishandled and accidents occur, the methane released into the atmosphere from seawater will exacerbate the global greenhouse effect problem. Furthermore, seabed mining may also disrupt the stable balance of the Earth’s crust, causing instability at the edges of the continental shelf and leading to seabed collapses, which can even result in massive tsunamis with catastrophic consequences. There is already evidence suggesting that large-scale natural releases of such gases in the past contributed, to some extent, to drastic changes in Earth’s climate. The tsunami that caused devastation in Northern Europe 8,000 years ago was also very likely caused by the massive release of such gases. There are mainly three mining plans. The first is the pyrolysis method. Taking advantage of the property that \"flammable ice\" decomposes when heated, methane vapor is released from it in a solid state. But the difficulty with this method is that it is hard to collect. The porous media on the seabed are not concentrated in a single \"area\" or as large masses of rock, but are rather distributed fairly evenly. How to lay the pipes and collect them efficiently is an issue that needs to be addressed urgently. The second option is the pressure reduction method. Some scientists have proposed burying nuclear waste underground and using the effects of nuclear radiation to break it down. But they all face the same problem of laying pipes and collecting efficiently as in the pyrolysis method. Option three is the “substitution method”. Research has shown that by liquefying CO2 (which is easy to do) and injecting it into the ocean at depths of over 1,500 meters (it’s not necessary to reach the seafloor), carbon dioxide hydrates are formed. These hydrates have a greater density than seawater, so they sink to the bottom of the sea. If CO2 is injected into seabed methane hydrate reservoirs, since CO2 forms hydrates more easily than methane, it may \"displace\" the methane molecules in the methane hydrates, thereby replacing them. But if methane clathrate leaks during extraction, large amounts of methane gas are released and enter the atmosphere through seawater. Methane has a greenhouse effect 21 times greater than that of CO2; therefore, if such leaks are not controlled, the global greenhouse effect will increase rapidly. As the atmosphere warms up, sea water temperatures will rise as well, and ground temperatures will increase as well, which will lead to the spontaneous decomposition of \"flammable ice\" on the seabed, creating a vicious cycle. Therefore, extraction must be controlled so that the methane gas released can be effectively captured. The extraction of combustible ice from the seabed involves complex technical challenges, so it is still in the development stage; it is estimated that 10 to 30 years will be required before commercial extraction can begin. In fact, China, the United States, Canada, India, South Korea, Norway, and Japan have all launched their own research programs on combustible ice. Japan has built 7 exploration wells, with the aim of starting commercial exploitation by 2010. The United States has also accelerated its efforts in recent years, hoping to begin commercial exploitation on the seabed or in permafrost regions by 2015. It is evident that \"flammable ice\" brings not only new hopes to humanity but also new challenges; only through rational and scientific development and utilization can it truly bring benefits to mankind.