The impact of humans on peatlands is increasingly negative and has locally resulted in the total annihilation of peatlands. Whereas the relationship between people and peatlands in the past may often have been balanced and mutually enriching, recent developments have resulted in huge areas of peatlands being degraded as a result of drainage (oxidation), deforestation, fire and pollution.

Human exploitation has destroyed almost 25% of the mires on Earth: of this destruction, 50% is by agriculture, 30% by forestry, 10% by peat extraction, and 10% by infrastructure development. Compared to other continents, Europe has suffered the greatest losses in mires, both in absolute and relative terms. Peat formation has stopped in over 50% of the original mire area, of which possibly 10-20% does not even exist any more as peatland (Joosten 1997). In Western Europe, many countries have lost over 90% of their peatland heritage, with the Netherlands leading with almost 100% of its natural peatlands being destroyed.

Asia and North America, including the vast extent of Siberian and sub-arctic peatlands, have incurred the least losses. Large-scale reclamation of tropical peat swamp forests in Southeast Asia which started only in the 1960s has destroyed over 120,000 km² of this habitat. Large areas have been left without peat soil as a result of oxidation and fires. Over 90% of peat swamp forests in Southeast Asia have been impacted by deforestation, conversion, drainage and legal or illegal logging, to the extent that they are significantly degraded and have turned from being carbon sinks into net sources of carbon (Hooijer et al. 2006).

On a global scale human exploitation may have destroyed 800,000 km² (20%) of mires on Earth: 50% of these losses are attributable to agriculture, 30% to forestry, 10% to peat extraction, and 10% to infrastructure development (Joosten and Clarke 2002).

As a result of continuing exploitation, the global mire resource is decreasing by approximately 1‰ per year, but in some regions (southern Africa, Southeast Asia, Central Asia) the current annual losses of peatlands can be counted in whole percentages and may result in the annihilation of the natural peatland habitat in this century (Silvius and Giesen 1992, Hooijer et al. 2006). Peat swamp forest area decline in insular South-east Asia is twice that of other forest decline (Hooijer et al. 2006). Most mire and peatland losses in future are expected to result from drainage and infrastructure development.

Unsustainable use of peatlands can have significant environmental and socio-economical side effects. These may be exacerbated by externalities and feedback mechanisms such as climate change (El Niño, sea level rise). Exploitation of peatlands may bring short-term benefits, but the loss of peatland ecosystem functions involves irreversible changes with large long-term impacts, both on-site and off-site. On-site changes result in habitat destruction with significant implications for local biodiversity, productivity and ecosystem services. Off-site effects may be felt at local, regional and global scales.

Also peat fires can have major collateral impacts, including losses of timber and other natural resources, regional public health problems, as a result of the haze, and major economic losses in transport and tourism sectors (Tacconi 2003).

Even though far fewer mires have been destroyed by peat extraction than by agriculture and forestry, this practice is most damaging to bogs over the short-term. Peat extraction is still ongoing today, particularly in Europe, and remains a serious local threat.

Drainage of peat leads unavoidably to land surface subsidence and carbon emissions. Most land-use practices on peatlands require drainage. This results invariably in subsidence of the peat body owing to physical collapse and compaction of the dehydrated peat, together with lowering as a result of loss of organic matter by oxidation. Subsidence may be as much as 500 mm in the first year of drainage and proceeds at rates of 10-100 mm in subsequent years depending on local conditions (Wösten et al. 1997). Consequently drainage and overall site hydrology are very difficult to manage, which results in technical management difficulties, declining water quality and smaller harvests. The exposure of peat layers to oxygen leads to oxidation of the organic material, while drying out of peatlands also leads to increased occurrence of fires, causing huge emissions of CO₂.

Changes to the physical and chemical properties of peat soil caused by drainage increase the susceptibility of peatlands to soil erosion and fire. The changing land management practices in tropical peatlands have greatly increased the susceptibility to physical degradation (subsidence), chemical degradation (oxidation) and fire, with particularly extensive fires associated with ENSO-related droughts in Indonesia since 1982. Similar effects of peatland drainage have been observed in Europe, with large parts of Russia and major cities like Moscow being covered in peat smoke for months on end in some years. Huge fires were, in the past, also known from Western Europe.

Intensive grazing on temperate and highland peatlands leads to increased phosphate P-output to surface water (Tetzlaff and Wendland 2004). It creates compaction and the exposure of the peat soil results in oxidation and erosion.

Peatland conversion for different kinds of uses often leads to fragmentation of the remaining natural or semi-natural peatlands. Large-scale conversion and intensive use of peatlands has in various parts of the world led to anthropogenic landscapes with ‘islands’ of remnant peatland habitats. Even when these fragments are protected for their wildlife and aesthetic values, their long-term sustainability is questionable, when their ecohydrological system has been destroyed (Charman 2002).