A simple metal pole planted in a meadow in Cambridgeshire, England, highlights the long-term impact of agricultural drainage on peatland subsidence. Installed in 1852 by landowners worried about the effects of drainage on the surrounding soil near the former Whittlesea marsh, the pole was anchored in bedrock and cut at the ground level at that time. Today, it extends nearly 4 meters above the current ground level, revealing that the terrain has sunk significantly since the 19th century. At Holme Post, the ground is now 2.75 meters below sea level, making it one of the lowest points in Great Britain. The subsidence occurs due to the oxidation of peat after drainage. In undisturbed peatlands, water saturation prevents oxygen from reaching the organic material. When drainage ditches are dug, air enters, allowing microorganisms to break down the organic matter. This process releases carbon dioxide and reduces the volume of the soil. In temperate regions like Europe and the United States, peatlands can sink by about six centimeters per year immediately after drainage, with the rate slowing to around one to three centimeters annually after a century. This subsidence creates a self-reinforcing cycle. As the ground sinks, the ditches become less effective, requiring deeper excavation. This further speeds up the oxidation of peat, leading to even more subsidence. In the English Fens, this has shifted the natural balance between the land and the rivers. Now, rivers are higher than their floodplains, held back by tall embankments as the land level drops. The ditches, originally intended to keep water out, have led to fields sinking below the water level they were meant to escape. Large portions of the Fens are now below sea level, with 40% of Lincolnshire and 50% of Cambridgeshire affected. Despite this, drainage has created some of the most fertile agricultural lands in the UK. The East Anglia Fens alone produce 22% of England’s total agricultural output and 33% of its fresh vegetables, supporting a rural economy worth an estimated £3.1 billion annually. Nearly half of England's best agricultural land lies in the Fens, which contribute a fifth of the country’s harvests and a third of its vegetables. However, maintaining the protective infrastructure in the region is expected to cost between £6 and £9.4 billion, a sum that does not cover the reinforcements needed to cope with climate change, which is expected to increase both flooding and drought in the area. Every cracked road, every leaning power pole, and every outdated pumping station reflects the ongoing subsidence caused by the continued use of the land. This phenomenon is not limited to England; peatlands converted to agricultural use across the northern hemisphere have released 72 billion tons of carbon between 850 and 2010, with 40 billion tons emitted between 1750 and 2010. Only half of these emissions have been offset by carbon absorption from natural peatlands. In Ireland, pastures on former peatlands emit up to eight million tons of carbon dioxide annually, one of the country's largest greenhouse gas sources. Everywhere ditches have been dug to drain peatlands, the same pattern of subsidence follows, often resulting in land that ends up lower than the water it was meant to repel.