coastal wetlands

The human footprint on Earth

February 6, 2025 By EarthWise Leave a Comment

The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it. But the impact of human activities on our planet continues to grow. Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it. Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert. Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly. Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia. Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise. The effects of this on the planet are increasingly evident. Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn. The massive wildfires in and around Los Angeles have made major changes in the local landscape. Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs. Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high. These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Salt Marshes And Climate Change | Earth Wise

May 5, 2023 By EarthWise Leave a Comment

Salt marshes are coastal wetlands that are flooded and drained by salt water brought in and out by the tides. These low-lying wetlands are also sometimes called tidal marshes because they occur in the zone between low and high tides. These wetlands are some of the most biologically productive ecosystems on Earth.

Cape Cod’s beautiful salt marshes are as important as they are iconic. They act as carbon sinks, protect coastal development from storm surge, play an outsized role in nitrogen cycling, and provide critical habitats for many fish, shellfish, and coastal birds.

According to scientists from the Marine Biological Laboratory in Woods Hole, Massachusetts, more than 90% of salt marshes around the world are likely to be underwater by the end of the century.

Since 1971, scientists from the Marine Biological Laboratory have mapped vegetative cover in Great Sippewissett Marsh in Falmouth, Massachusetts, to examine whether increased nitrogen in the environment would impact species of marsh grass. Because of the length of the study, the researchers were also able to investigate the impacts of climate change on the ecosystem, especially those driven by accelerating sea level rise.

The research team found that increased nitrogen favored higher levels of vegetation and accretion of the marsh surface. However, the researchers found that salt marshes will not be able to outpace the submergence from global sea level rise – no matter how much nitrogen is applied.

Sea level rise is the biggest threat to salt marshes around the world. Mitigating some of these projected losses is critical in order for salt marshes to continue to provide their important ecosystem services for people and the planet.

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Most of the World’s Salt Marshes Could Succumb to Sea Level Rise by Turn of Century

Photo, posted September 27, 2011, courtesy of Chris M Morris via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Recovering Marine Life By 2050 | Earth Wise

May 27, 2020 By EarthWise Leave a Comment

Marine life has faced challenges for a long time. There have been centuries of overfishing in many places and pollution of various types has been especially harmful in recent decades. But despite all of this, a new scientific review published in the journal Nature contends that marine life in the world’s oceans could be fully restored in as little as 30 years provided that aggressive conservation policies are adopted.

The research spotlights the strong resiliency of ocean animals and cites the successful recovery of a number of marine species, including humpback whales.

The study indicates that nations around the world must agree to designate 20 to 30 percent of the oceans as marine protected areas, institute sustainable fishing guidelines, and regulate pollution. These measures would not come cheaply. The estimated cost would be around $20 billion a year.

However, the report also estimates that the economic return on this investment would be tenfold and would create millions of new jobs. Rebuilding fish stocks and maintaining sustainable fishing policies could increase global profits of the seafood industry by over $50 billion a year. Conserving coastal wetlands could save the insurance industry more than $50 billion a year as well by reducing storm damage.

A major sticking point, however, is climate change. Climate change is increasing ocean temperatures and driving acidification. Unless these changes are brought under control, the restoration of marine life is not going to be successful. We have reached the point where it is within our power to choose between a future with a resilient and vibrant ocean or an irreversibly disrupted ocean. Whether we embrace that challenge remains to be seen.

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Marine Life Could Recover By 2050 With the Right Policies, Study Finds

Photo, posted April 20, 2012, courtesy of Matthias Hiltner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.