After last week's snow storm there was a lot of noise about whether this was caused by climate change, whether it refuted global warming, or if it was just weather in the Midwest. This brought me back to how much difficulty there is in understanding the relationship between weather, climate change and global warming. Without getting into whether we are observing a natural or man-made phenomena, I am going to take a stab at this clarifying these relationships.
- The underlying phenomena driving climate change is global warming – the Earth is heating up. This is a simple, verifiable fact.
- This heating occurs unevenly, largely do to local and regional variables, (e.g., air and ocean currents, atmospheric moisture, relative albedo, carbon sequestration, urban heat islands, etc.).
- As the Earth gets warmer, ocean and air currents change, distributing heat and moisture in new patterns. Warmer oceans also mean more moisture is available to the atmosphere.
- We experience these changes in our daily lives through weather, which is highly sensitive to such forcings.
- Over longer periods, these effects produce changes in climate, which can dramatically alter the physical and biological characteristics of place on local, regional and global scales.
- These changes in climate can also create feedback that amplifies these effects locally, regionally and globally.
As an added note, evidence suggests that historically, dramatic shifts in global climate have not tended to occur gradually, but quite often occur in time periods as short as a decade or less. Again, this is not inconsistent with non-linear systems.