Impacts of a Warming Planet
The impacts of global warming are widespread, already noticeable, and variable by geography. A review of scientific data shows that global ocean temperatures, where most solar heat is trapped, have risen 1.5 degrees over the last century, with the greatest increase occurring over the last 4 decades. This may not seem like a big difference, but it has profound impacts, including a rise of sea levels, more severe coastal storms, changing precipitation patterns, both heavier rains, and extended droughts, and more extreme temperatures, including prolonged heat waves.
The potential challenges posed by changing climate have been known for decades, but it wasn’t until the turn of the century that natural and social scientist and policymakers began to seriously consider, in research, publications, and governance the enormous impacts and implications on modern society.The Intergovernmental panel on climate change’s fifth assessment report, authored through a collaboration of 831 scientists from leading research institutions around the world examine global and regional climate changes and their impact on human activities and economic sectors. Their data, and those analyzed by National Ocean and Atmospheric note common observations.
Rising Temperatures
In the state of Florida, the greatest impact that man has had on climate is through the land surface. Temperatures have risen along with the southeast Florida coast by over a degree F in the last 40 years, especially in the summer months. Much of this can be attributed to urban development, where cities built of concrete and asphalt now absorb and hold more heat than the natural environment they replaced
Rising Sea Levels
Global sea level has risen 19 cm (7.5 inches) between 1901 and 2012, and that the rate has accelerated to a rate of 3.2 cm/decade in the last 20 years, matching tide gauge and satellite observations. Sea Level rise can be attributed to glacial melt, as well as thermal expansion, (warm water expands in volume.) Local sea level rise can be either higher or lower than the global average due to differences in prevailing winds and ocean currents and underlying geologic processes like crustal rebound.
Hurricanes
In the future, it is likely that we may experience strong, if not more frequent tropical storms and hurricanes. The IPCC report states that it is more likely than not that there will be a human-caused increase in intense hurricanes by 2100 in some regions. Common sense would dictate that warmer ocean temperatures would lead to more strong storms, as a 1.8 degree F increase in water temperature increase water vapor by 7 %. But predicting more intense and more frequent storms is not that straight forward. In addition to the heat and moisture from the oceans’ surface, hurricane formation is predicated on favorable atmospheric conditions with little wind shear. Climate models are unclear how atmosphere factors may affect hurricanes in the Atlantic region in the future, so it is not certain that all hurricanes will be strong, only that some may be very strong.
Heavier Rains and Drought
The underlying theory is that as the atmosphere warms, it can hold more moisture and that will lead to more extreme rainfall events. Conversely, warmer temperatures will cause greater evapotranspiration rates leading to more periods of drought. In short, we could be looking at both more drought and extreme rainfall events in a warming climate. Here in Florida, the climate is subject to both drought and heavy precipitation. Because of the nature of our summer convective rainy season and the influence of El Niño/La Niña cycle, the year-to-year variability of rainfall overwhelms other trends or patterns. Florida will continue to be vulnerable to drought, especially when dryness in winter and spring extends into the summer season. Florida is also subject to heavy precipitation events, whether from tropical systems, mid-latitude lows and fronts that tap the Gulf Moisture, or slow-moving summer thunderstorms. It is uncertain if one trend will prevail, but it is likely that we will experience greater extremes of both.
