What Is Global Warming?

The use of renewable energy is one tool to reduce greenhouse gases emissions. John Hicks/Photographer's Choice/Getty

A discussion of global climate change, also called global warming, can get very complicated very quickly. Fortunately, it can be explained rather simply. Here are the basics you need to know about climate change:

Warmer Land and Sea

The climate has warmed and cooled many times during Earth’s geological history, over millions of years. However, the global increase in mean temperature we have observed in the last decades has been both unusually rapid and quite large. It translates to warmer air temperatures and warmer sea water almost everywhere on Earth.

Less Ice, Less Snow

This increase in temperatures has led to increased melting of most of the world’s glaciers. In addition, the thick Greenland and Antarctica ice sheets are losing volume, and sea ice covers an increasingly small portion of the Arctic while also getting thinner. The winter snow cover in most areas of the U.S. is thinner and does not last as long over the winter. Sea levels are rising, both because of the melting ice, and because warmer water expands and takes up more space.

Less Predictable Weather

While the word climate refers to long-term statistics on many aspects of temperature and precipitation, weather is a more immediate phenomenon, and is what we feel outside everyday. Global climate change is transforming our experience of weather events in different ways depending on where we live. Common changes include more frequent heavy rain events, regular winter thaws, or persistent droughts.

All About the Greenhouse Effect

Human activities release in the atmosphere many gases that create a greenhouse effect. Greenhouse gases hold back the sun’s energy that had been reflected by Earth’s surface. This heat is then redirected towards the ground, increasing temperatures. Most of the observed warming can be attributed to these gases.

How Are Greenhouse Gas Produced?

The most important greenhouse gases are carbon dioxide and methane. They are released when we extract, process, and burn fossil fuels such as coal, oil, and natural gas for electricity, manufacturing, and transportation. These gases are also produced during industrial activities, when we clear land for housing and farming, and during some agricultural activities.

Are Sun Cycles to Blame?

The Earth’s surface temperature rises and falls with slight changes during natural sun cycles. However, these solar cycles and the changes they produce are well understood and much less significant than those driven by greenhouse gases.

Global Warming Consequences

The consequences of global warming include more frequent coastal flooding, heat waves, extreme precipitation events, food insecurity, and urban vulnerability. The global warming consequences are being felt (and will be felt) differently in different parts of the world. Global climate change often affects more those who do not have the economic means to develop ways to adapt to the changes. Of course, climate change affect not only humans but the rest of the living world as well. 

Global warming has few positive consequences. Gains in agricultural production, often cited as positive, are easily offset by increases in pest problems (including invasive species), droughts, and severe weather events.

We can respond by mitigating global warming, which is to reduce it by curbing greenhouse gas emissions. We can also capture carbon dioxide, the most abundant greenhouse gas, out of the atmosphere and store it safely on earth. We can, in addition, adapt by investing in infrastructure, transportation, and agriculture in order to continue living with the inevitable changes brought by global warming.  

What Can You Do?

Most importantly, reduce your greenhouse gas emissions, whether you contribute as an individual or as a business owner.