Saving Earth

2021 marks the 51st anniversary of Earth Day the beginning of a critical decade to save our planet’s health. Learn about what we’ve accomplished and failed to accomplish in the last 5 decades, and explore some of the key environmental problems we have yet to solve. Discover the promising solutions that do exist for these challenges and meet the figures and organizations—past and present—who have led the charge. Get involved while we celebrate Earth and take care of our precious, fascinating, beautiful home!  

Learn about the major environmental problems facing our planet and what can be done about them

Since the end of the last ice age, humans have developed tools and machines and have modified the land for agriculture and long-term settlement. As the population has grown and new technologies have spread across cultures and continents, more and more of the planet’s resources have been pressed into serving the species. In the process, human activities have disrupted the natural order of the environment by depopulating and eliminating species and adding harmful chemicals to the air, water, and soil—activities that are changing the climate and the structure and function of ecosystems, as well as the biological communities they contain. 

Solving the critical environmental problems of global warming, water scarcity, pollution, and biodiversity loss are perhaps the greatest challenges of the 21st century. 

Will we rise to meet them?

Meet the Big Four Problems

Human action has triggered a vast cascade of environmental problems that now threaten the continued ability of both natural and human systems to flourish. Here are four major environmental problems this site will be showcasing.


Pollution is one of the most serious problems facing the planet, but it may be one of the easiest to overcome. Learn about how humans cause and can remedy our pollution problems.

Water Crisis​

This crisis poses the most immediate risk to human life and regional stability. Learn about the causes and effects of water scarcity at the global level, and about some of the strategies for addressing it.

Global Warming​

The greenhouse gas emissions from human activities are changing the face of Earth. Explore the ways climate change is occurring and what we can do about it.

Biodiversity Loss​

Nonhuman life on Earth is suffering greatly at human hands. Learn the major threats to biodiversity and what can be done to keep our organisms from being lost forever.

"Future generations will judge us harshly if we fail to uphold our moral and historical responsibilities."

Ban Ki-Moon, former secretary-general of the United Nations

The Underlying Causes

While it is difficult to distill the major drivers of our planet’s environmental problems into a brief list, the following articles provide insight into some of the overarching causes behind many of our most pressing crises. Read about the Industrial Revolution, population growth, consumerism, and other big forces that have led to an Earth that needs saving.


The Big-Picture Solutions

While it is easy to become discouraged by the current and projected impacts that these environmental problems have on Earth’s biosphere, a number of solutions have emerged. Most involve changing the way we view the planet and its resources and leveraging regulatory and policy tools to establish sets of rules that incentivize the sustainable use of Earth’s resources.


"The more clearly we can focus our attention on the wonders and realities of the universe about us, the less taste we shall have for destruction."

Rachel Carson

Test your Knowledge

We have no shortage of daunting challenges ahead of us, but gaining awareness is one of the first steps! How much do you know about the various environmental problems that face you, your community, and your planet? Take our quizzes to find out. 

Featured quizzes

Featured videos

Advocacy for Animals Blog

Britannica Podcast Series

Take Action

The issues facing Earth are big, but imagine the difference we could make if we all took steps to address them. Learn about the small but important changes you can make in your daily life to reduce your greenhouse gas emissions, save water, help wildlife, and limit pollution.