There are few things more romantic than navigating the narrow streets of Barcelona: The layers of history, the ease of getting lost, the just-around-the-corner sense of discovery. I found it intoxicating. Pair the cobbled streets with public art throughout, wide boulevards for contrast, and put it all next to the sea graced with a relaxing beach and full marina (and don't forget lovely weather most of the year), and you've got Barcelona.

Not only is it the sixth-largest metropolis in Europe, with 1.6 million people living within the city limits, it's also an incredibly popular place for tourists from throughout Spain, the continent, and abroad. But one of the noticeable downsides of the city has long been that it's crowded, and it can get very hot in the summer. It has so little green space that the city heats up a full 10 degrees more than the surrounding suburbs, meaning a steamy-but-tolerable 87-degree day outside the city becomes genuinely uncomfortable inside city limits.

With climate change predicted to heat the city even further in coming years, green spaces that get a jump-start on growing now will save lives — and tourist dollars, later. (Parks, gardens, and even simply curbside trees can reduce a city's heat-island effect to keep it cooler, as well as mitigate air pollution.) While Barcelona has a number of large parks on the upslope areas of the mountains that frame the city, they all lie outside the congested city center, which is where cooling is needed most.

With so few trees and plants to handle air pollution within the city — the greenery buffers noise as well — Barcelona was clearly in need of some verdant spaces. But how do you make space in a several-thousand-year-old metropolis that long ago monopolized every extra space there is? You get creative.

It's all about corridors

In the city's Biodiversity and Green Infrastructure Plan, there are tips for any urban area that can't spare large tracts of land for parks, yet wants to green up the cityscape. It includes five new gardens that will be linked together and to existing green spaces, via corridors of green. Wide boulevards are shaded by trees, but rather than vehicular traffic running between them, further landscaping and pedestrian walkways will predominate. (And the video above shows how the modern city integrates green space into the urban core.)

The gardens are pulled from a motley collection of space-finding solutions: one garden will surround an existing city square where traffic used to run; another will be made by opening formerly private gardens to the public, a third comes via a former unused industrial area, and a fourth will be created out of a former military barracks. Another will come by clearing a courtyard block of workshops from the 1920s where people are currently squatting (and this park is controversial for that reason).

Green roofs are also part of the city's plan — as are green walls and even gardens set up in construction sites — temporary oases that will cool and freshen areas otherwise decimated while buildings go up. Other creative solutions include adding plantable areas to existing parks and replacing old concrete with permeable versions, so rainwater can saturate the ground instead of running into city sewers and out to the sea.

The city came up with the plan by following a set of four goals, which include working actively to minimize species loss via preserving habitat; creating green corridors for pollinators like birds and insects to travel along; maximizing the value given to "natural services;" and lastly to "make the city more resilient to emerging challenges such as climate change." In addition to doubling the number of trees, the goals also mean that bird and bat boxes, beehives atop roofs and even special habitats for insects will be part of the plan.

This isn't just about creating new green spaces, but a more functional ecosystem as a whole for the city.

This holistic plan could be a model for other cities; such a combination of smart changes means that every citizen of Barcelona gets an extra square meter of green space — which will make an already beautiful city even more gorgeous — not to mention healthier for the people who are lucky enough to live there.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.