How often do volcanoes erupt?

Under control

UK air space is to be reorganised – the first wholesale change since the 1950s – to improve flight times and reduce delays. It was Britain that pioneered air traffic control with the world’s first control tower – a timber shed on a platform 15ft above the ground – at Croydon Aerodrome in 1920. The tower was given responsibility for all aircraft airborne, with which it had basic radio connections. From 1928, control centres in Norfolk and Kent allowed radio signals to be ‘triangulated’ for the first time, allowing the position of an aircraft to be determined even if the pilot was lost.

Battle ready

The government seemed to downgrade its target to spend 3 per cent of GDP on defence to an ‘aspiration’. Who spends the most, and least, on defence as a percentage of GDP in 2023 (or latest figures)?

MOST

Ukraine 36.7

Eritrea 20.9

Libya 15.5

Lebanon 8.9

Algeria 8.2

Saudi Arabia 7.1

LEAST

Haiti 0.1

Ireland 0.2

Zimbabwe 0.2

Papua New Guinea 0.3

Ghana 0.4

Guatemala 0.4

World Bank

Hot stuff

Tourists were nearly caught in an eruption of Mount Etna on Sicily. How often do volcanoes erupt?

– There are 47 volcanoes worldwide considered to be in a state of eruption.

– 54 have so far erupted this year.

– 65 erupted over the course of 2024.

– 333 volcanoes are recorded as having erupted since 1960, many multiple times.

– 528 have erupted since 1800.

– The average number which have erupted a year since 2010 is 80.

Global Volcanism Program, Smithsonian Institute

Force fields

How much land does the MoD own?

– On 1 April this year, it owned 230,800 hectares of land and foreshore, 0.9% of the total surface area of Britain.

– It held rights over a further 110,600 hectares, 0.5% of the UK land area.

– The land is broken down as: training (76%); R&D (10.5%); airfields (4.4%); barracks/camps (3.8%); and storage/supply depots (2%).