Weather is temperature, precipitation (rain, hail, sleet and snow) and wind, which change hour by hour and day by day. Climate is the general long-term character of the weather and the nature of its variations that we experience over time. The Earth’s climate has changed on many timescales in response to natural factors. Over thousands of years we see the Earth move in and out of ice ages. At the other extreme, El Nino (variations in surface temperature of ocean water across the tropical eastern Pacific Ocean) come and go every few years, temporarily raising the Earth’s temperature. Over the course of the last century there has been an unusual increase in the average global temperature, accompanied by changes in extremes of weather. The term ‘climate change’ is often used to refer to changes to our climate arising from human activities.

Answered by the Met Office team, OPAL Climate Centre.

Organisms that live in the perpetual darkness and extreme pressures of the deep sea have a variety of bizarre and ingenious adaptations to enable them to survive. In the twilight zone between 200 and 1,000 metres, animals are often equipped with huge eyes to find food and mates, and to evade predators. The giant squid Architeuthis dux was eyes the size of dinner plates. In the total darkness found past 1,000 metres, many deep-sea animals have evolved light-producing organs that are used either for recognition or as lures to catch prey.

With no phytoplankton (microscopic plants) available as a primary food source, the inhabitants of the deep must rely on a slow, steady rain of waste food particles from above, or hunt and scavenge in the darkness. Sometimes, a shipwreck or the carcass of a large organism such as a whale or the trunk of a tree will arrive on the seabed and the slow pace of life is transformed as a range of animals take advantage of the nutritional bonanza, which can last a number of years.

Guy J Baker, Marine Biological Association of the UK