Britain's fields, parks and lawns were thriving areas of fresh greenery, just before summer arrived. Then, everything was burnt to a crisp, with a yellow and golden hue and now landscapes as old as thousands of years have been revealed as green outlines against yellow backgrounds. July was the driest month ever recorded in England and Wales and droughts have affected part of Britain in four of the last five years. As heatwaves become more frequent with global warming, the most affected areas are coming to be lawns and parks since any available water has been directed to homes and farms. With this, England faces a recurring question: "What happens to its green and pleasant land if summers like these continue?"
As a group, grasses are good at surviving dry conditions and their resilience has helped make them one of the successful groups of plants on Earth. They now include more than 11,000 species and cover more than 40% of the Earth's land area, from tropical savannas to Arctic steppe. They are also much older than scientists once thought. The earliest fossil grasses date to around 55 million years ago, but distinctive mineral deposits in their leaves have since been found in fossilised dinosaur faeces from the late Cretaceous period, so it is now known that grasses were around tens of millions of years earlier. Grasslands spread across the world later, about 20-30 million years ago, when they took advantage of a climate that was becoming cooler and more arid. In those conditions, grasses could survive better than many other types of vegetation.
The main grasses used in British lawns are not necessarily as well adapted to dry conditions as some of their relatives elsewhere. But even species already native to northern Europe and well adapted to cool, damp conditions have ways of surviving drought. They can slow water loss from their leaves and, where possible, send roots deeper into the soil in search of moisture. However, under really dry conditions, such as those right now, they have no choice but to shut down and wait for better conditions. They move what water remains to the parts of the plant that will produce new leaves, which are protected deep inside the outer leaves. These outer leaves dry out and die, giving some of their water to the critical growing parts, which survive and are ready to produce new leaves when it rains again. The growing centres also accumulate sugars that help draw in water and protect their cells from drying out. But after previous droughts, dead expanses of stalks have slowly recovered when rain comes back and these lawns will return with time, too. What remains as a question is whether this will be repeated in the future when such harsh summers repeat. This poses the British public with the situation of accepting yellow grass or switching to varieties that are better for warmer conditions. However, climate change is not just making the weather warmer, but also making it more difficult to predict, a phenomenon that has been called "global weirding." But ultimately, there's no magic grass variety that will keep Britain green and pleasant whatever the weather and people will have to adapt to the warmer, less predictable climate along with its consequences.
