Sunlight is essential to almost all life on Earth. However, you can have too much of a good thing, as some in central and northern Europe, currently enjoying abnormally high temperatures and strong sunlight, are realising. A new report from the World Health Organisation (WHO) highlights the dangers associated with sunlight, and specifically ultraviolet (UV) light - around 60,000 people die each year from diseases associated with exposure to sunlight. As figures for diseases attributable to sunlight are often difficult to ascertain, the WHO compiled an upper and lower estimate for both the number of 'disability adjusted life years' (or DALYs) from UV, and the number of annual deaths for its report, 'Global Burden of Disease of Solar Ultraviolet Radiation', the first report of its kind. The figures are high - around 1.5 million DALYs per year or 60,000 deaths. Almost all of the non-fatal diseases could be 'avoided through appropriate UVR exposure (minimum required to maintain vitamin D adequacy)', according to the report. UV light can cause the three types of skin cancer - cutaneous malignant melanoma, squamous cell carcinoma and basal cell carcinoma. The majority of deaths come from cutaneous malignant melanoma, which can be treated effectively if found only at early stages. Around 90 per cent of global instances of cutaneous malignant melanoma are due to sunlight. A fourth, extremely rare form of cancer, Squamous cell carcinoma of the cornea or conjunctiva, is another possible heath risk. Other diseases of sunlight include - Photoageing: premature skin ageing, also known as solar keratoses, can be pre-cancerous. Solar keratosis is entirely attributable to UV light exposure. - Sunburn: may be severe and can in extreme cases require skin grafts. The resulting disease burden from sunburn is attributable to UV light exposure. - Cortical cataracts: long-term exposure to UV light can lead the body to produce a natural reaction - the build-up of material to protect the eye. Unfortunately, this can lead to blindness. Around five per cent of all cataract-related disease is attributable to UV light exposure. - Pterygium: a wing-shaped growth on the surface of the eye. 40-70 per cent of the Pterygium disease burden is attributable to UV light exposure. - Reactivation of herpes of the lip (RHL): UV exposure causes the reactivation of the herpes simplex (or 'cold sores'). 25-50 per cent of this global disease burden is attributable to UV exposure. However, the WHO does not advocate a move indoors. The sun has known beneficial effects, for example through elevating vitamin D levels within the body, and anecdotal improvements to general well-being, which could be simply attributable to people enjoying sunlight. To put this into perspective, if the benefits from sunlight exposure were removed, the WHO estimates that 3.3 billion DALYs would be lost to bone diseases such as rickets or osteoporosis. 'This global assessment of the health risks of UV radiation provides a good basis for public health action. We all need some sun, but too much sun can be dangerous - and even deadly. Fortunately, diseases from UV such as malignant melanomas, other skin cancers and cataracts are almost entirely preventable through simple protective measures,' said Dr Maria Neira, Director for Public Health and the Environment at WHO.