First, climate is different than weather. Weather is the daily, weekly, or even monthly atmospheric event, such as rainfall or sunshine or even hurricane and tornado events. However, climate is ”the average course or condition of the weather at a place usually over a period of years as exhibited by temperature, wind velocity, and precipitation” (Merriam-Webster, 2021). So when we are talking about climate change, it is not the daily changes in weather or the fact that winter in upstate NY is still cold, it is the long-term changes in the weather patterns over time.
“The warming of the climate is unequivocal”
International Panel on Climate Change (IPCC), 2007
How do we know it is caused by humans?
The planet is warming. Historically (as in for billions of years), Earth has had slow and long term warming and cooling periods. These changes take a really long time (like tens of thousands of years) to occur and are called glacial and interglacial periods.
However, since 1950, the changes in the climate have occurred wicked fast in comparison to the last 10,000 years. Between 10,000 and 6,000 years ago the global mean temperature change was about 1 C increase. From this 1 C increase 6,000 years ago to about 1900 the global mean temperature change decreased decreased the same 1 C.
From 1950 to today, the global mean temperature has increased about 1 C (NASA, 2021). It took the Earth 4,000 years and nearly 6,000 years to make a 1 C change. But somehow (I will explain below) there has been the same change in only 70 years.
GLOBAL LAND-OCEAN TEMPERATURE INDEX
Data source: NASA’s Goddard Institute for Space Studies (GISS). Credit: NASA/GISS (NASA, 2021)
This change happened (AND WILL CONTINUE TO HAPPEN) because humans have been pumping chemicals into the atmosphere. Carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone (O3) contribute to atmospheric warming (ACS, 2021). The introduction of oil use in place of coal has changed the energy use of humans. CO2 and methane are byproducts of using oil for heating or burning and are pushed into the atmosphere. As a result, more energy is trapped in Earth’s atmosphere and has been being stored in the ocean.
Water has a much higher heat capacity than the atmosphere. This is how much energy is needed to heat a specific amount of water or air by 1 C. The energy to heat 1 kg of air is 1158 J per 1 C; whereas, the energy required for seawater is 3850 Joules for the same change.
So what?
The additional energy in earth’s system for the past 70 years has been collecting in the ocean. Slowly creating this warming effect. However, the warming takes time after the energy storage. Meaning, the changes we see now are caused by energy that was stored years ago. Even if all new gases to the atmosphere stopped and we somehow found a way to stop increasing the energy today, the ocean would still warm and the atmosphere would still warm.
This is why it is CRITICAL to make immediate changes so that my grandchildren will have a stable world, not a changing one like myself and my children will see.
Climate change does not meaning that next year the winter storms will stop and that there will no longer be cold storms, but that in time, the storms will change. There are numerous symptoms that come with a changing climate.
To learn more about what the future holds, read this post about Climate Change Symptoms.