Why in News

• Human rights groups Amnesty International and Human Rights Watch, and Ukraine’s ambassador to the USA, accused Russia of using thermobaric weapons in the ongoing war against Ukraine.

About thermobaric weapon

• A thermobaric weapon is one of the most devastating weapons as they cause significantly greater destruction than a conventional bomb of comparable size.
• It uses oxygen from the surrounding air to generate a high-temperature explosion.
• It is also known as an aerosol bomb, fuel-air explosive (FAE), or vacuum bomb.
• The fuel-air explosive is one of the best-known types of thermobaric weapons. Different fuels can be used, including toxic powdered metals & organic matter containing oxidants.
• It can be fitted to hand-held launchers, can be fired as rockets from tank-mounted launchers, or dropped from aircraft.

Mechanism

• These weapons generally work in two stages.
• As the weapons hit the target, a first explosion occurs and it will open the bomb’s fuel container, releasing a cloud of fuel and metal particles that spreads over a large area.
• Then a second explosion occurs to ignite the aerosol cloud into a giant ball of fire and send out intense blast waves that can cause huge destruction.

Comparison with conventional weapons

• Conventional explosives consist of flue-oxidizer premix-like black powder which contains fuel and oxidizer in the ratio of 25:75. On the other hand, thermobaric weapons are almost 100% fuel and rely on atmospheric oxygen.
• The blast wave of a thermobaric weapon lasts longer than that of a conventional condensed explosive. However, their dependence on atmospheric oxygen makes them unsuitable for use underwater, at high altitudes, and in adverse weather.

International law

• Thermobaric munitions are not explicitly prohibited for use against military targets.
• However, their use against civilian populations in built-up areas, schools, or hospitals, could attract action under the Hague Conventions of 1899 and 1907.
• The use of weapons in indiscriminate attacks – those that cannot distinguish between combatants and civilians – is forbidden by the Geneva Conventions. A thermobaric weapon might be targeted specifically at military installations but it will kill civilians too.