• Pollution
  • Biodiversity Loss
  • Global Warming
  • Water Crisis
  • Causes and Solutions
  • Quiz
  • Take Action
  • Britannica Presents Earth’s To-Do List for the 21st Century

    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?

  • Global Warming hero

    Global Warming

    Collectively, the weight of human beings and their activities are changing the face of Earth. By the end of the 20th century, greenhouse gas emissions from human activities had become so great that they had begun to influence global and regional temperature and precipitation patterns. Find out how global warming affects climate and explore the different ways climate change is occurring and what has and could be done to manage the problem. Read more ›

  • Biodiversityloss Hero

    Biodiversity Loss

    Nonhuman life on Earth is suffering greatly at human hands, and many species have already been lost forever due to our actions. Explore the major threats to biodiversity and learn what can be done to protect the planet’s precious plant and animal life. Read more ›

  • Water crisis Hero

    Water Crisis

    Of all the natural crises we humans face, the global water crisis is perhaps the one that poses the most immediate risk to human life and regional stability. Learn about the causes and effects of water scarcity at a global level, and about some of the strategies and solutions that can help us address it. Read more ›

  • Factory pumping air pollution


    Pollution is one of the most serious problems facing the planet, but it may be one of the easiest to overcome, since it relies largely on what we humans decide to create and release into the environment. Learn about various types of pollution, how each affects the environment, and how people and governments at all levels can work to limit, reduce, and eliminate the harmful effects of pollution. Read more ›

  • First Earth DaY – 1970

    20 million

    Americans demonstrated for a healthy, sustainable environment in massive coast-to-coast rallies

    Earth Day 2000


    Environmental groups in a record 184 countries reached out to hundreds of millions of people

    Know the Causes

    Human action has triggered a vast cascade of environmental problems that now threaten the continued ability of both natural and human systems to flourish. While it is difficult to distill the major drivers of these 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.

  • population-hero

    Human Population

    Population is the number of inhabitants occupying an area and is continually modified by births, immigrations, deaths, and emigrations. Read more ›

  • Common-Pool Resources

    Common-pool resources are resources made available to all. Some examples are fisheries, forests, and groundwater basins. Read more ›

  • Industrial Revolution

    With few exceptions, many of the world’s modern environmental problems began or were greatly exacerbated by the Industrial Revolution. Read more ›

  • Tragedy of the Commons

    The tragedy of the commons highlights the conflict between individual and collective rationality when it comes to the consumption of natural resources. Read more ›

  • The Rise of the Machines: Pros and Cons of the Industrial Revolution

    The Industrial Revolution is the period in which agrarian and handicraft economies shifted rapidly to industrial and machine-manufacturing-dominated ones. Read more ›

  • Consumption

    Consumption is the use of goods and services by households. Read more ›

  • Mass Production

    Mass production is the application of the principles of specialization, division of labour, and standardization of parts to the manufacture of goods. Read more ›

  • Ecological Footprint

    Ecological footprint is a measure of the demands made by people on our global natural resources and is one of the most widely used measures of humanity’s effect upon the environment. Read more ›

  • Know the Solutions

    While it is easy to become discouraged by the current and projected impacts that these environmental problems have upon 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.

  • Environmental Policy

    Environmental policy is designed to prevent or reduce harmful effects of human activities on ecosystems. Read more ›

  • Environmental Law

    Environmental law is the field encompassing the principles, policies, directives, and regulations enacted and enforced by local, national, or international entities to regulate human treatment of the nonhuman world. Read more ›

  • Sustainability

    Sustainability is the long-term viability of a community, set of social institutions, or societal practice. Read more ›

  • Environmental Infrastructure

    Environmental infrastructure serve to protect human health and to safeguard environmental quality. Read more ›

  • Environmentalism

    Environmentalism is a political and ethical movement that seeks to improve and protect the quality of the natural environment. Read more ›

  • Ethical Consumerism

    Ethical consumerism is a form of political activism based on the premise that purchasers in markets consume not only goods but also, implicitly, the process used to produce them. Read more ›

  • shopping contributes to consumer culture

    Anticonsumerism Movement

    The anticonsumerism movement is a social ideology that decries the excessive purchasing and consumption of material possessions. Read more ›

  • Natural Resource Management

    Natural resource management is how societies manage the supply of or access to the natural resources they rely on for survival and development. Read more ›

  • Precautionary Principle

    The precautionary principle is an approach in policy making that legitimizes the adoption of preventative measures to address potential risks to the public or environment associated with certain activities or policies. Read more ›

  • Regulation

    A regulation is, in government, a rule or mechanism that limits, steers, or otherwise controls social behaviour. Read more ›

  • What Is Environmental Economics?

    Environmental economics is a subdiscipline of economics that applies the values and tools of mainstream macroeconomics and microeconomics to allocate environmental resources more efficiently. Read more ›

  • How Environmental Economics Places Value on the Environment

    Economists have long tried to accurately determine the value of environmental goods to society. Read more ›

  • Environmental Economics Continued: Other Instruments and Future Directions

    Once the market inefficiency relating to a particular environmental good is understood, policy makers can correct for the inefficiency by employing any number of instruments. Read more ›


    Which gases play an important role in climate change? What percentage of scientists agree that humans contribute to this process? Test your knowledge of this “hot” topic with this quiz.


    There are a lot of ecosystems in the world. How much do you know about the different types of ecosystems?iption


    Do you know about the threats facing nonhuman life on Earth? Take this quiz to test your knowledge.