Climate Confusion: It's Not Just Weather?

Whether you hear about it on Local on the 8s, at the end of a morning news broadcast, or from handy notifications pinging on your phone, chances are you're familiar with the phrase "Today's weather outlook is ... ". Weather reports are those daily reminders to bring an umbrella, pack sunscreen or drink water or think about rescheduling a trip entirely. But, when those same sources mention climate science, it's clear that for some, the difference between our weather and our climate is, well, cloudy. So, what exactly is weather? What is climate? And how are they different?

What Is Weather?

At its core, weather is what's happening anywhere in Earth's atmosphere hourly or daily. Four main factors drive it: temperature, humidity, air pressure and wind. These factors make days mild, sweltering, frigid, sticky or dry. They set air masses moving across continents and transfer heat into the ocean, thereby changing weather conditions across the globe.

Weather affects us in small and big ways. A sprinkle might dampen school recess, while an intense hurricane means that entire neighborhoods should evacuate to safety. Weather events can even impact people far away, like when a Midwest drought leads to smaller harvests and empty shelves in East Coast grocery stores. Given weather's effects, humans have been studying and measuring it for centuries.

The days of relying solely on thermometers or barometers are long gone, though. For decades now, organizations like the National Oceanic and Atmospheric Administration (NOAA) and National Weather Service (NWS) have been analyzing global weather data gathered through more advanced tools, like satellites. These advances have improved our understanding of weather events and our ability to predict things like major storms, saving lives in the process.

What Is Climate?

Collecting weather data year after year also reveals another important aspect of a region's environment: its climate. Weather conditions over a long time—decades or more—determine an area's climate. After all, one dry day in a rain forest won't turn it into a desert. By averaging a region's weather data over 30-year periods, we get the ranges of temperature, humidity, air pressure and wind usually observed over time. Understanding this connection of weather informing climate helps us grasp climate science and discuss climate change.

Taking averages over these longer periods means we can more easily see patterns and trends without getting distracted by unique data points, like a very snowy winter or an intense summer heat wave. But if extreme events happen more often, or we regularly measure higher or lower temperatures season after season, those averages eventually change—indicating a change in climate.

When Trends Change

Climate scientists always expect some shifts when comparing climate averages. But the shifts they're seeing in the 30-year averages around the globe over the last century are abnormal. Average temperatures are creeping upward faster. Ice and snow cover are disappearing more rapidly. Sea levels are gradually rising. In short, the rate at which the world's climate is changing is increasing, and the shifting patterns are affecting regions differently.

In Maryland, average air temperatures have risen by 2.5 degrees Fahrenheit since the 1880s. Warmer air increases evaporation, drying out soil and vegetation. Warm air can also hold more moisture, leading to more rainfall. This can lead to flooding since parched soil can't absorb water fast enough. Maryland now gets an average of 4.5 inches more rain annually than at the beginning of the 20th century. These changes also unequally impact distinct parts of the state. Western counties are warming more than eastern ones, while the eastern portions are coping with higher chances of coastal flooding.

What's Behind This Change?

These changes are happening faster than expected—and outpacing historical change—considering that weather shapes climate over a long time. While natural events can and have altered climate in the past, people are a primary driver in today's changes. More specifically, the carbon emissions from fossil fuels that power our lives are driving rising temperatures globally.

Burning fossil fuels releases excessive amounts of gases like carbon dioxide and methane, leading to higher concentrations of these carbon emissions in our atmosphere. The structures of these gas molecules, unlike those of other atmospheric gases like oxygen and nitrogen, absorb and trap heat very efficiently and act like a blanket for the Earth. The more emissions, the more heat is trapped, the higher our land and sea temperatures, until we see shifts in our daily weather and our long-term climate.

Our activities have disturbed the climate. That means we can also act to reduce our impact and slow the rate of climate change by making changes within our households and routines. For example, we can cut down on food waste, opt to walk or take public transit, shop for local goods, and replace old appliances and cars with high-efficiency or electric models.

We can also enact change by making sure we support legislators fighting for climate-forward policies on local, national and international stages. Climate's response to changes we make will take some time—which means the best time to become part of the climate solution is now.

Image of Earth's atmosphere as seen from the International Space Station courtesy of NASA.