Two UC Davis researchers examine a water sample from Lake Tahoe


Climate Science

The Earth’s climate is changing. Temperatures around the world are rising. Traditional weather patterns are shifting, and the number of extreme weather events — hurricanes and extreme temperatures — are happening more often.

In the early 1960s, scientists recognized an emissions increase in carbon dioxide into the atmosphere has grown beyond their expectations. Later they discovered that methane, nitrous oxide and other gases were also rising. Because these gases trap heat and warm the Earth, as a greenhouse traps heat from the sun, scientists concluded that increasing levels of “greenhouse gases” would increase global warming. As surface and water temperatures rise, human, animal and plant life respond. Scientific studies document these responses. In doing so, science builds a foundation for understanding how our lives are impacted by climate change and what we can do to slow or reverse changes.

A hot sunset over sacramento

Defining Climate Science

The study of climate science doesn’t focus just on what makes changing climate important; it studies how it will affect people around the world. Rising global temperatures bring with them the potential to raise sea levels, change precipitation and local climate conditions. Climate change could alter forests, crop yields and water supplies as we know them. Changing climate also affects human and animal health and their ability to exist in certain ecosystems. As a rangeland quickly changes into expanding desert, for instance, it forces native species to adapt or move elsewhere.

History of Climate Science

The modern science of climate prediction dates back to the late 1700s at Monticello, where for more than 50 years Thomas Jefferson was a consistent weather observer. While Jefferson may not have been the first climate scientist, certainly not officially, his continuous record of weather observations in America and in Europe, and even in the mid-Atlantic, are practices still used to this day to measure precipitation and daily temperature range.

smoke stacks spewing pollution

The Future of Climate Science

Human activities have altered the chemical composition of the Earth’s atmosphere. As greenhouse gases increase — primarily composed of carbon dioxide, methane and nitrous oxide — the heat-trapping properties of these gasses indisputably cause the Earth’s climate to respond. However, it remains uncertain just what exactly that response is.

Climate scientists believe factors such as aerosols, changing uses of land and others are playing important roles in climate change, but their influence and exact impact remain highly uncertain.

The United States has created a number of organizations and programs coordinating at a global level extensive research into climate change. These organizations and universities work with private organizations, states and other municipalities to address climate change and global warming.

Satellites and other real-time monitoring tools now help calculate actual surface temperatures across the globe and measure how much they’ve been warming. These calculations are achieved measuring the Sun’s radiation reflected and absorbed by the land and oceans.

With time, scientists from around the world will work together to solve climate change, using new technology and computer modeling to simulate and predict Earth’s ever-changing conditions.

north america from space with sunrise coming over the left side

What is Climate?

“What’s the difference between weather and climate?” It’s a commonly asked question, but it’s really just a matter of time. Where weather is defined by atmospheric conditions over a short period of time, climate is defined by atmospheric behavior over relatively long periods of time.

Weather is the change we see outside on a day-to-day basis. Some days are hotter than others. It might rain one wintery day, and then not the next.

When referring to climate, though, we look at the long-term averages of daily weather. If summers feel warmer now than they did 30 years ago, then it’s possible recent climate may have changed.

To complicate things further, researchers believe there are even shorter-term climate variations. So-called climate variability can be represented by periodic or intermittent changes related to El Niño, La Niña, volcanic eruptions or other sudden and punctuated changes.