Weather and climate are two foundational concepts in understanding climate change. While distinct, their interactions can be confusing. It’s important to consider how their dynamics affect the planet and every aspect of our existence. Both climate and weather are expressed with the same variables; scientists use temperature, precipitation, humidity, and wind to describe both. So, what’s the difference between the two?
Time.
Weather is the short-term behavior of the lower atmosphere, while climate is the long-term average patterns of weather. The weather has a much more direct effect on day-to-day human activity, focusing on how atmospheric phenomena create events that affect us from minutes to months. Weather constantly varies and changes rapidly between minutes, hours, days, weeks, and seasons. Just because one summer in West Texas had a lot of rainfall does not mean the next summer will be the same. Additional conditions we associate with weather include cloudiness, brightness, visibility, and atmospheric pressure. These characteristics are directly based on the amount of energy in the Earth system, where that energy is, and how it travels. Of course, the ultimate source of the energy driving weather is the Sun. Many local surface conditions affect weather patterns, with numerous factors such as generating or reducing sunshine, rain, clouds presence, high winds, hail, snow, sleet, flooding, hurricanes, blizzards, thunderstorms, and heat waves.
The National Weather Service oversees all short- and long-term weather forecasting in the United States. The National Weather Service combines ground radar and weather instrument measurements with orbital satellites images to produce continuously updated computer models predicting near-term weather conditions. It has more than 25 warnings and categorizations for weather events to be on the lookout for (such as Flash Flood Watches and Warnings, Coastal Flood Watches and Warnings, Fire Weather Watches, and Hurricane Watches and Warnings). By its very nature, this process is complex and not always accurate, especially when looking beyond a week. The National Weather Service shares its continuously updated data with local and regional news outlets that pass the information to the public with its extensive nationwide network.
While weather is immediately important to daily life, the climate is just as vital. Regional climate conditions can impact crop yields, water supplies, forests, sea levels, and more. Humans depend on the environment to provide essential services to live, and those services similarly rely on specific climate conditions to thrive. Regardless of our technologically innovative and creative management of natural resources, we are still ultimately bound by the limitations of what the Earth system can provide. Observed measurements relevant to climate include averages of temperature, humidity, precipitation, sunshine, wind velocity, and the intensity and frequency of fog, frost, hailstorms, and other weather events over a long period of time in a particular location.
Changing climate is the result of long-term shifts in daily weather averages. Typically, the climate is measured with 30-year averages of a particular area’s weather. The length of 30 years allows the range of natural weather variations from one year to the next to be mathematically accounted for. For example, by looking at many different measures of water in a region, from rain gauge data to lake, aquifer, and reservoir levels, combined with satellite observations, scientists can conclude if a particular winter was drier than average. If that dry pattern continues over many following years, that would mean the climate in the area has changed. There can also be short-term changes in the climate that are natural in the Earth system, which happen in periods faster than 30 years but slower than standard weather events. Examples include intermittent changes from El Niño, La Niña, or volcanic eruptions, but these patterns can also shift over time. The climate in a single area—like the Gulf Coast—is called a regional climate. The average climate around the globe is described as the global climate. The term “global climate change” refers to a pattern of observed changes in weather and temperature data worldwide over many years, such as rising temperatures.
Often the terms “global warming” and “climate change” are used interchangeably, but global warming is just one aspect of climate change. They are related, but not the same. Global warming is the increase in average global temperatures because of the rise in atmospheric greenhouse gas concentrations from anthropogenic emissions. This changes the atmosphere’s chemical composition, impacting the amount of energy trapped in the Earth system (our first post details the greenhouse effect). Climate change is the long-term alterations in precipitation, temperature, wind patterns, and other measures of the Earth’s climate, both on a regional and global scale, and at a rate faster than average due to human activity. Some observed changes of climate change, as described by the US Geological Survey, are quoted as follows:
- Temperatures are rising worldwide due to greenhouse gases trapping more heat in the atmosphere.
- Droughts are becoming longer and more extreme around the world.
- Tropical storms are becoming more severe due to warmer ocean water temperatures.
- As temperatures rise, there is less snowpack in mountain ranges and polar areas, and the snow melts faster.
- Overall, glaciers are melting at a faster rate.
- Sea ice in the Arctic Ocean around the North Pole is melting faster with the warmer temperatures.
- Permafrost is melting, releasing methane, a powerful greenhouse gas, into the atmosphere.
- Sea levels are rising, threatening coastal communities and estuarine ecosystems.
As touched on earlier, the characteristics of the landscape also play a role in weather and climate patterns, affecting sources and sinks for heat, water dynamics, wind generation, and how pressure systems behave. Land cover, which humans change through our land-use practices, impacts carbon storage and the concertation of atmospheric greenhouse gases. By changing the land, we can contribute to or lessen the rate of climate change. This also works both ways. As the climate changes and alters regional weather behavior, land cover and how we use it are changed. We see how agriculture in Texas is transitioning from traditional to drought-tolerant, flood or heat-resilient crops and species that take advantage of longer growing seasons. In other words, crops that have greater economic value under climate change, including those that may store more carbon in roots and soils, get prioritized. Warmer average temperatures impact water storage and vegetation cover, influencing irrigation systems. This happens not only to resources humans value but to all ecosystems. Deserts are expanding into rangeland, and typically biodiverse and resilient wetlands are disappearing with rising sea levels and soil erosion. These changes cause significant losses of wildlife habitat and the species that live in them. Understanding the interactions between climate, weather, and land use are essential for climate adaptation and mitigation efforts.
Changing climates have worldwide consequences that vary by region. A typical maxim is that “wet places get wetter, and dry places get drier.” While not universally true, this is a good way to consider the regional effect of climate on the weather. While this could seem beneficial, it’s anything but. Dry water-limited areas will be challenged as already scarce resources become rarer. The same can be said for wet regions, as experiencing dangerous flood events is the opposite of ideal. Scientists utilize sophisticated computer models to project global changes across the planet. They suggest that “long-term effects of climate change will include a decrease in sea ice and an increase in permafrost thawing, an increase in heatwaves and heavy precipitation, and decreased water resources in semi-arid regions.” Again, the US Geological Survey summarizes:
- North America: Decreasing snowpack in the western mountains; 5-20 percent increase in yields of rain-fed agriculture in some regions; increased frequency, intensity and duration of heatwaves in cities that currently experience them.
- Latin America: Gradual replacement of tropical forest by savannah in eastern Amazonia; risk of significant biodiversity loss through species extinction in many tropical areas; significant changes in water availability for human consumption, agriculture and energy generation.
- Europe: Increased risk of inland flash floods; more frequent coastal flooding and increased erosion from storms and sea-level rise; glacial retreat in mountainous areas; reduced snow cover and winter tourism; extensive species losses; reductions of crop productivity in southern Europe.
- Africa: By 2020, between 75 and 250 million people are projected to be exposed to increased water stress; yields from rain-fed agriculture could be reduced by up to 50 percent in some regions by 2020; agricultural production, including access to food, maybe severely compromised.
- Asia: Freshwater availability projected to decrease in Central, South, East and Southeast Asia by the 2050s; coastal areas will be at risk due to increased flooding; death rate from disease associated with floods and droughts expected to rise in some regions.
Changing climate conditions also increase the number and intensity of extreme weather events, which Texas has already started experiencing over the last decade. Increased global surface temperatures cause more droughts and make storms more severe. Warmer conditions increase the rate of water evaporation into the atmosphere, which heightens the strength of storms. Greater atmospheric heat and warmer ocean surface conditions generate faster winds during tropical storms. Areas not previously subject to coastal erosion and flooding become exposed from rising sea levels.
Changes in the global climate impact weather patterns worldwide, influencing shifts in regional climates. Changes in the climate also affect human health, ecosystem biodiversity and stability, and the overall resiliency of the Earth system for human habitation. It’s essential to understand the interaction between weather and climate and get a sense of how the changes we’re causing affect their behavior. How humans respond to shifting conditions will determine how intense these changes ultimately become.
Additional resources to learn more and share, including lesson plans for the classroom:
Videos:
- Weather vs. Climate (Crash Course Kids)
- Weather vs. Climate (Mike Sammartano)
- What’s the difference between weather and climate? (NASA Climate Change)
Websites:
- Climate FAQs (USGS)
- Climate Kids (NASA)
- Climate Maps (NOAA)
- National Forecast Maps (NWS)
- National Weather Service (NWS)
- Weather versus Climate (cK-12)
- What’s the Difference Between Weather and Climate? (NASA)
- What’s the Difference Between Weather and Climate? (NCEI)
Lesson Plans: