Even if millions of tourists didn't visit Greece annually, there would still be far too much environmental abuse in this beautiful country, because awareness of the need for environmental protection in Greece is a fairly recent development, with far too few laws supporting it. But millions of tourists severely compound the problem..
It is essential to conserve water in Greece, where this resource is all too scarce in many places, especially on very dry islands. Long showers are to be avoided, or heavy water usage of any kind, especially during the months from late spring (after the winter rains) and up until November.
Greece is known for its grand displays of spring wildflowers, many of which include many species of orchids. The latter should be enjoyed visually, but not gathered., and in general, though it is a Greek custom to gather wildflowers for wreaths on May Day, it is always best never to gather flowers of which one sees only very small clusters.
There has been a long ongoing uphill battle in Greece to protect the endangered loggerhead turtle, especially on the island of Zakynthos, on some of whose gently shelving beaches these turtles have traditionally dug their nests and laid their eggs. Successful reproduction is essential to survival of these creatures, though heavily impacted by tourist activity on those same beaches. Lights from hotels disorient the hatchlings, who often perish because they head towards those lights instead of towards the sea, which, under natural conditions would be the brightest thing around, thus triggering their instinct to move towards it. Loud noise from tourist bars and restaurants is also a deterrent to the approach of females from the sea seeking to dig their nests in the sand, and nests are often destroyed by compacting of sand by vehicles driven on the beaches, or puncturing of them by beach umbrellas. Hatchlings also get entangled in beach chairs left on the beach. Do not camp on beaches where these turtles nest, or even walk on them at night, or talk loudly or play music near them at night. By no means drive bikes or cars on such beaches, and don't put up breach umbrellas or leave beach beds out at night. There are educational centers in many places where the loggerhead turtle nests. Educate yourself as to their habits and learn which areas to avoid at night. (The repetition of the words 'at night' here is quite deliberate, for it is at night that serious damage can be done to these ancient and threatened creatures).
The first marine sanctuary in Europe is found on and around the island of Alonissos and its islets in the Sporades island group, which is mostly to the east of the city of Volos and the Pilio peninsula. This sanctuary was established to protect the very rare and endangered Mediterranean monk seal, though there are also many species of birds, including rare falcons on some of these islands.
There has been increasing awareness of the need for better treatment of animals in Greece during the past few decades, with many animal welfare groups established all over the country, in both cities and on the islands, in many cases (though not all) started by concerned foreign residents. Most of these groups deal with the need for sterilization and adoption of stray dogs and cats, as well as for medical care and increased public awareness of the need to treat such animals kindly. Programs have been established in some places for adoption of stray animals by foreigners who take the animals back with them to their own countries, though strict procedures must be followed for this that conform to respective national laws. As in many other places in the world, many people (in farms and cities alike) have dealt with unwanted , freely reproducing animals, by poisoning them or killing them by other rather appalling means. These days, though one will see dogs and cats which are loved by local Greeks, there are still far too many cases of brutal 'disposal' of unwanted animals, as well as ill treatment and neglect. Many village dogs are kept day and night on short chains, from a very young age, either by themselves or near other such chained dogs, often close to chicken coops, where their barking is meant to frighten away weasels. Hunting dogs have it a little better, as they are taken out for hours at a time more than once a week, especially in winter, during hunting season (though many may stay chained up during the other months). Many animals (mules, donkeys, horses, sheep, goats) have their feet tightly hobbled so that they won't leave poorly fenced pastures; and many animals are tethered in full sun during hot summer days with no shade available to them. These latter practices will be slower to change than the situation with dogs and cats, but there is always hope. It certainly can't hurt to write to the EU about the need for laws concerning these things, or to talk with local officials.
There are far more forests in Greece than many foreign tourists realize, because much tourism was focused during the first few decades (from the 1960s through the 80s) on the islands, especially those in the Cyclades ( Mykonos, Santorini, Paros, etc.), where there is no forest. There are, however, islands which have extensively forested areas, though much decimated by fires, including Lesvos/Lesbos (also called Mytilini), Hios (Chios), and Thassos, in the north and northeast Aegean, Samos (east Aegean), and smaller patches of forest here and there on other islands, including the large island of Evia (Euboea). There is also extensive forest in the Peloponnisos (Peloponnese), and in central and in the northern Greek regions of Ipiros, Macedonia and Thrace. Many fires that have wiped out forest in Greece (especially on the islands mentioned), are well known to have been set deliberately by developers who want to build on land with protected forest status (ie. off bounds to building). It is the same rapacious interest group that is behind the present effort to change the definition of exactly what constitutes 'forest' in Greece, with the aim of removing much land from its present legally protected status. Foreign visitors are urged to be extremely vigilant when camping, or when smoking cigarettes during the hot dry summer months in open areas. The lovely hiking trails on Mt. Ymittos (Hymettus) to the east of Athens (near the beautiful monastery of Kesariani), are a case in point, as is Parnitha, to the north of Athens, which is also a favorite hiking area near Athens. Given the fact that these forested areas constitute the main forest in the dry region of Attiki (Attica), it would be tragic to lose them to carelessness. Certainly such caution must be exercised everywhere in Greece, though, not just in Attica.