Why a country this small has more coast than Spain

What the country is made of

Denmark is a Nordic country in northern Europe, consisting of the Jutland peninsula and several islands in the Baltic Sea known collectively as the Danish Archipelago. It lies south-west of Sweden and due south of Norway, and its only land border is with the German state of Schleswig-Holstein, which was a Danish possession until the wars of the nineteenth century removed it.

The island count is the striking figure. Denmark has 443 named islands, and 1,419 islands above 100 square metres, of which 72 were inhabited as of 1 January 2007. The largest are Zealand and Funen, with Bornholm sitting separately out in the Baltic east of the rest of the country.

The scale is small and the perimeter is not. A circle enclosing the same total area as Denmark would have a diameter of 234 kilometres, and yet the tidal shoreline runs 8,750 kilometres. The general coastline, which excludes most of the offshore islands, is 1,701 kilometres, and the difference between those two numbers is the whole geography of the country.

Why nothing is high

The highest point in Denmark, Møllehøj, reaches 171 metres, which is lower than a good many buildings. The country has no mountains, no significant uplands and very little relief of any kind, and the reason is that the ice took it all away.

Denmark sits on soft sedimentary rock that was repeatedly overrun by ice sheets, and what the ice left behind was a surface of moraine, outwash plain and meltwater valley rather than anything carved out of hard rock. The gentle hills of eastern Jutland and the islands are glacial deposits, and the flat western half of Jutland is outwash sand and gravel dropped by rivers running off the melting ice.

That division runs north to south through Jutland and it is the only significant terrain distinction in the country. East of the line is heavier clay soil, better farmland and a more varied surface; west of it is sandy, poorer ground, historically heath, which was planted with conifers and reclaimed for agriculture over the past two centuries.

The consequence for everything else is that Denmark has no natural obstacles. No mountain range divides it, no river system is large enough to matter as a barrier, and the difficulty of moving around the country has always been water rather than terrain. That is why Danish engineering history is a history of bridges and tunnels rather than of passes and mountain roads. The bridges are the modern answer to it. The link across the Great Belt between Funen and Zealand and the crossing between Copenhagen and Malmö turned a country of separate islands into a single road and rail network within a generation, and they changed the economic geography more than any policy did. A town that was two ferries from the capital and is now ninety minutes from it is a different place.

What the water does

A country of a peninsula and several hundred islands is a country whose internal transport problem is crossing things. The straits between Jutland, Funen and Zealand were the historical obstacle, and the bridges and tunnels built across them in the past half century have changed how Denmark functions more than any works before them, infrastructure.

The seas themselves are the other half. Denmark sits at the entrance to the Baltic, which is why the country was able to charge a toll on shipping passing through for centuries, and it borders both the Baltic and the North Sea across a shoreline that includes some of the shallowest and most tidal water in Europe.

The Wadden Sea along the south-western coast is the extreme case and the reason the tidal shoreline figure is so large. It is a system of tidal flats, salt marsh and barrier islands where the sea retreats several kilometres twice a day, and it is inscribed on the World Heritage List as a natural property shared with Germany and the Netherlands. It is a principal stop for migrating birds on the East Atlantic flyway, precisely because a tidal flat exposed twice a day is an enormous feeding ground.

Fresh water is unremarkable and abundant. The rivers are short, none of them navigable in any serious sense, and the country's drinking water comes almost entirely from groundwater, which is a rare position among developed countries and one that makes agricultural pollution a direct rather than an indirect problem. What is spread on a field in Denmark reaches the tap eventually, and the regulation of farming reflects that in a way it does not in countries drawing surface water.

What the sea has done to the shape

The Danish coast is not fixed and never has been. Soft glacial deposits meeting a shallow tidal sea produce a shoreline that erodes in one place and accretes in another, and the map of the country has changed within recorded history in ways a rock coast would not.

The western coast of Jutland is the clearest case. Facing the North Sea directly with nothing but sand between the waves and the land, it has required continuous defence, and the dunes, groynes and nourishment programmes along it are maintained as infrastructure. Storm surges have breached it repeatedly and rearranged the barrier islands behind it.

The eastern coasts are gentler and were shaped by the drowning of a glacial landscape rather than by wave attack. The fjords of eastern Jutland are not fjords in the Norwegian sense but flooded meltwater valleys, which is why they are shallow and broad, and useful as harbours rather than deep and cliffed, and why almost every Danish town of any age sits at the head of one.

Rising sea level therefore lands on a country unusually exposed to it. A low, soft, long coastline with major cities and most of the agriculture close to sea level makes coastal protection a permanent and growing national expense, and the planning horizon for it is measured in centuries rather than in budget cycles.

Where the country sits strategically

Denmark controls the entrance to the Baltic Sea, and everything about its historical position follows from that single fact. The straits between Jutland, the Danish islands and Sweden are the only route between the Baltic and the North Sea, and a state holding both sides of them for much of history could tax, close or protect the traffic through.

That is why a small country was a European power for centuries and why it was repeatedly attacked. The Sound Toll made Danish kings rich, the ambition to control the Baltic drew Denmark into wars with Sweden it eventually lost, and the position kept the country relevant to larger powers long after its own strength had declined.

The modern version of the position is different in form and identical in logic. Denmark sits on the shipping lanes into the Baltic, on the fixed links between Scandinavia and continental Europe, and, through Greenland, on the Arctic routes that are opening as the sea ice retreats. A state of under six million people holds geography that several much larger ones care about, which is a durable source of influence and a durable source of pressure at the same time.

The land border is the other half. It runs with Germany across the base of the Jutland peninsula, it has moved twice within the past two centuries, and the region on either side of it holds minorities of the other nationality whose rights are protected by agreement between the two states. A frontier that was fought over twice is now one of the quieter borders in Europe, and the arrangements that made it quiet, minority schooling, cultural funding and political representation on both sides, are studied elsewhere as a model.

What the climate is

The climate is temperate, characterised by cool to cold winters with a mean January temperature of 1.1 °C and mild summers with a mean July temperature of 16.5 °C. The most extreme temperatures recorded since observations began in 1874 have been well outside those means in both directions and rarely.

Two things moderate it. The sea is close to everywhere, which compresses the range at both ends, and the prevailing westerlies bring Atlantic air across the country rather than continental air from the east. The result is a maritime climate with a great deal of cloud, wind and moderate rain distributed through the year rather than concentrated in a season.

Wind is the feature with economic consequence. A flat country surrounded by shallow sea in the path of Atlantic weather systems has the best combination of conditions in Europe for wind generation, and the country's position in offshore wind technology follows directly from having a domestic reason to develop it decades before anyone else needed one.

Daylight varies enormously. At this latitude midsummer gives light late into the evening and midwinter takes it away by mid-afternoon, and the effect on how the country lives, eats and socialises through the year is substantial. A great deal of what is described abroad as Danish domestic culture is an adaptation to five months of darkness.

How the land is used

Denmark is farmed about as intensively as land can be. A very large share of the total area is farmland, the fields are large, and the agriculture is industrial in organisation despite employing only about 2% of the workforce.

Livestock is the dominant activity by value, with pig production on a scale that far exceeds domestic consumption, and the environmental consequence is nitrogen. Nutrient runoff into groundwater and into the shallow enclosed seas around the country is the country's central environmental problem, and it is a direct product of the land use pattern rather than a side effect of it.

Forest covers a much smaller share than in the rest of the Nordic region and most of it was planted. The heaths of western Jutland were afforested through the nineteenth and twentieth centuries in a deliberate national project, so a Danish forest is generally a plantation of a known age rather than a remnant of anything older. The country was almost entirely cleared of its original woodland centuries ago, and what stands now is the result of a policy decision about how much forest a country ought to have.

The built environment is dense along the eastern side. Copenhagen and the towns of eastern Jutland hold most of the population, western Jutland and the smaller islands are emptying, and the difference between a country that is uniformly flat and uniformly accessible is that people concentrate for economic reasons rather than geographical ones, and depopulation in the west and on the small islands is a policy problem rather than a consequence of terrain. Denmark: economy goes into what the land produces and Denmark: travel the coast a visitor would go to.