Climate change is causing "chaos" for UK nature because of rising average temperatures, changing seasons and increasingly unpredictable weather, the National Trust has said in its annual review.
It is almost certain that 2023 will be the hottest year on record and probably in the last 120,000 years, with the Met Office forecasting 2024 to be hotter still.
The UK has already warmed by more than 1C above the pre-industrial average, leading to winters shortening and summers lengthening.
Extreme heat and drought is becoming more common and this year the UK recorded its hottest June, with the river Derwent in the Lake District, traditionally one of England’s wettest areas, drying out for the third consecutive summer.
This was followed by intense storms in the autumn, which caused widespread flooding.
High winds and waves battered the southern shoreline with one area in Dorset seeing 15 years of erosion in a day.
Ben McCarthy, head of nature and restoration ecology at the National Trust, said: "The shifting weather patterns we’re seeing in the UK, particularly with the warmer temperatures we’re experiencing, is continuing to upset the natural, regular rhythm of the seasons, causing stress to wildlife and making it more susceptible to pests and disease.
"This loss of predictability causes chaos for the annual behaviours of animals in particular, but can also impact trees and plants."
Shorter winters mean there are fewer cold snaps to kill off tree pests such as the oak processionary moth, which has been spreading north from its traditional home in the Mediterranean.
It also makes hibernators like dormice wake up earlier, meaning they use more energy than they would normally, and red deer rut later in the year, which results in calves being born in the summer instead of spring – so they lose time to grow and put on fat for the winter.
Mr McCarthy said: "It’s these baseline changes that we’re seeing that are really worrying and what we should be taking more notice of, particularly when combined with extreme weather events, which makes things even more challenging."
National Trust rangers and gardeners are mowing grass later in the year due to warmer, wetter conditions, while some shrubs have been budding early, exposing them to cold snaps while depriving insects of nectar in the summer.
There were also algal blooms and low water levels as early as January in the Lake District and also in Port Stewart, Northern Ireland, over the summer.
East Anglia and Cornwall spent over a year in drought conditions after the extreme heat of 2022.
Keith Jones, national climate change consultant at the National Trust, said: "When you consider the extreme temperatures and heatwaves that have devastated parts of Europe and other countries this year, we have been extremely fortunate.
"We were just 1,000 miles away from experiencing a second year of serious drought and record-breaking temperatures which would have had huge consequences for nature, people and food production.
"But we can’t allow ourselves to be lulled into any sense of false security.
"In the near future we are likely to experience a combination of drought and high temperatures as well as high rainfall and flood – and we need to get ready for this new norm.
"Water is going to be key – not having enough and also not too much."
