What is Climate?
Climate change refers to the long-term (usually at least 30 years) regional or even global average of temperature, humidity, and rainfall patterns over seasons, years, or decades.
What is Weather?
Weather refers to atmospheric conditions that occur locally over short periods of time—from minutes to hours or days. Familiar examples include rain, snow, clouds, winds, floods, or thunderstorms.
To help better understand climate change, let’s explore some of the differences between climate and weather.
The Mediterranean
Let’s look at the Mediterranean region as an example. The Mediterranean has hot, dry summers and mild, wet winters.
Check-in
Question:
Can you think of any local examples where the climate has remained consistent, but weather patterns have been unpredictable?
What is Climate Change?
Climate change is a long-term change in the average weather patterns that have come to define Earth’s local, regional and global climates. These changes have a broad range of observed effects that are synonymous with the term.
- As we produce more greenhouse gases, the unpredictability of both climate and weather increases.
- Climate change doesn’t always make things warmer. Some areas have actually cooled as a result of climate change. Unpredictability and non-seasonal weather is the defining trend.
The climate change we are experiencing now is different from natural climate change.
Due to anthropogenic influence, our climate is changing at an exponentially faster rate compared to the normal processes that would change climate averages.
What causes natural climate change?
- variations in sun’s energy reaching Earth
- Changes in reflectivity of Earth’s atmosphere + surface (ex: land use changes)
- volcanic eruptions
- changes + trends in glacial-interglacial cycles
Imagine climate models as tools that predict temperature and environmental changes. When scientists only consider natural factors like the sun and volcanoes, the models show minor warming or even cooling. But, when we add in human activities—burning fossil fuels, deforestation, and industry—the models match the real temperature rise we see. This shows that natural factors alone can’t explain our current warming. Human activities, which release greenhouse gases, are the key drivers.
Check-in
Question:
Discuss the various factors that can naturally influence climate change. Which do you think has the most significant impact?
Greenhouse Gas Impact
Agricultural emissions are a significant contributor to total emissions in the U.S., at 10.6% of our total emissions within the U.S. The largest quantities of gases emitted in the agricultural sector are methane (NH4) and nitrous oxide (NO2), which have a much higher warming potential than CO2. As more emissions data is collected, our understanding becomes clearer, highlighting the urgent need to reduce emissions.
GHG Warming Potential
Greenhouse gases (GHGs) are not just limited to carbon dioxide (CO2). While CO2 is the baseline that other gases are measured from, there are other gases like methane and nitrous oxide that have a much greater warming potential. A greater warming potential means these gases remain in the atmosphere longer relative to the equivalent weight of CO2. Essentially, these gases stick around longer in the atmosphere and warm the planet much more. This also means that they can be a larger problem than carbon dioxide emissions, even if there are less of these gases being emitted relative to CO2.
The graphs above illustrate significant trends in heat wave characteristics from the 1960s to the 2020s.
- Heat Wave Frequency: The average number of heat waves per year has steadily increased, rising from about 2 in the 1960s to nearly 7 in the 2010s and 2020s.
- Heat Wave Duration: The average length of individual heat waves has grown from approximately 3 days in the 1960s to about 4 days in recent decades.
- Heat Wave Season: The annual length of the heat wave season has expanded significantly, from roughly 20 days in the 1960s to nearly 75 days in the 2020s.
- Heat Wave Intensity: The average temperature above the local threshold during heat waves has also increased, from around 2°F in the 1960s to about 3°F in the 2010s and 2020s.
These trends indicate that heat waves are becoming more frequent, longer, and more intense, with their season extending considerably.
Personal Impact:
Personal Impact
“A normal season does not seem like it happens anymore. It’s either really dry, or really wet. It seems like when we get rain, it’s apocalyptic… We got 5 inches of rain in about 1.5 hours, and I had a lot of soil loss… I see the impact for generations.”
– Thor Oeschner, Newfield, NY
Climate Change Impacts on Agriculture
Now that we understand climate change, let’s look at what the consequences of climate change mean for agriculture today.