Because of ever-growing awareness and concern among travelers, resorts today must offer them more than just skipping the daily delivery of fresh towels.
There is no one source or rating system, but there are organizations that collect information on "green" resorts (Sustainable Travel International and International Ecotourism Society), and some groups with a vested interest in travel dollars offer reliable awards for responsibility (the Tourism for Tomorrow Awards from the World Travel & Tourism Council, the Conde Nast Annual Green List and the Global Vision Awards from Travel & Leisure).
Here's a short list of beautiful places that are protecting the flora and fauna while helping out their local economies.
Hermitage Bay, Antigua, West Indies
Opened in December 2006, the Hermitage is a collection of 25 secluded cottage suites nestled along the turquoise waters of the Caribbean.
The resort shows respect for its location in many ways: The land was cleared by hand, and buildings were constructed with sustainably grown timber, no glass and very small amounts of concrete and steel.
The resort uses solar energy to heat water, serves locally grown fruit and vegetables, and helps increase the local hummingbird population by planting flowers and shrubs.
All kitchen waste is given to a local pig farmer, who in turn supplies the resort with pork. The beach is pristine. Rates start at about $700 per night.
Lapa Rios Ecolodge, Costa Rica
Lapa Rios is set in a private nature reserve spread over 1,000 acres of Central America's last remaining lowland tropical rain forest, which it will protect in perpetuity.
Built 350 feet above sea level, it offers paths where you can look over the forest canopy and enjoy breathtaking ocean vistas.
Considered a pioneer in eco-travel, Lapa Rios frequently collects awards from Conde Nast and Travel & Leisure as one of the world's most Earth-friendly addresses.
Rates start at about $200 per night.
Evason Phuket & Six Senses Spa, Thailand
This is one of several resorts from Six Senses, a leader in luxury eco-tourism since 1995.
Set on one of the world's more spectacular spots, Evason Phuket comprises 64 acres of tropical parkland overlooking the Andaman Sea.
The interior is as lovely as the exterior; all of the design elements, from the sconces to the netting over the beds, are exquisite.
The spa is top-notch. While you're enjoying an outdoor massage and an ocean breeze, guests can ponder the resort's biodiesel plant, composting area, herb and vegetable garden, nursery, wastewater treatment plant and fresh-water reservoir.
Rates start at about $250 per night.
Hapuku Lodge & Tree Houses, New Zealand
Two decades ago, when the local whaling industry was outlawed, the small city of Kaikoura, on New Zealand's South Island, found itself in difficulty.
Since then, it has been reinvented by Maori locals who have learned to sustain local marine life and appeal to tourists by nourishing the natural beauty of the land, with its dramatic mountains and surf-washed beaches.
The lodge, 7 miles north of Kaikoura, is surrounded by an expansive deer farm and a 1,000-tree olive grove. Lodge rooms offer views across the deer paddocks to the mountains, plus there are five treehouses nestled 30 feet above ground in the canopy of a native Manuka grove.
Rates start at about $350 per night.
Al Maha Desert Resort & Spa, United Arab Emirates
Forty-five minutes from Dubai, this ultra-luxurious resort offers 40 spacious bungalows set in 90 square miles of pristine desert landscape, with unobstructed views of the undulating sand dunes, dotted with palms, and the mountains beyond.
There are numerous opportunities for watching indigenous desert wildlife --the resort is on a reserve that protects several species -- and sightings of gazelles and oryxes (white antelopes) are common.
Al Maha's importance is global: Much of the region's desert habitat is rapidly disappearing amid the Gulf region's rapid development.
Rates start at about $1,100 per night.