What is Climate Change?
Climate change is a global phenomenon that includes any significant change in the climate that lasts for extended periods of time. Global warming, which refers to the observed increase in average global surface temperatures over the past several decades, is one facet of climate change. Other components include changes in precipitation, wind patterns, the cryosphere, and extreme weather events.
Over the past century, humans have released large amounts of CO2 and other greenhouse gases (GHGs) into the atmosphere. Most of these emissions have come from the combustion of fossil fuels, such as coal, natural gas, and oil; however, land-use changes, such as deforestation and agriculture, are also major contributors. According to the Intergovernmental Panel on Climate Change (IPCC), human activities have increased atmospheric concentrations of CO2 to their highest levels in at least two million years, and humans are the dominant cause of changes to the global climate since the mid-20th century.
GHGs act like a form of atmospheric insulation, trapping energy in the atmosphere and increasing global temperatures. GHGs allow ultraviolet radiation from the sun to enter the atmosphere, but they prevent a portion of that energy from escaping back into space. Though GHGs make just 0.04% of the atmosphere, they significantly affect the global climate. As a result, global average surface temperatures have increased by approximately 1.1ºC since 1880.
Climate Change in Northeast Ohio
Air Temperatures and Extreme Heat
Climate change is already having demonstrable effects on Northeast Ohio, and those will only get worse in the coming decades. Since 1950, annual average temperatures have warmed by 2.6˚F (1.5˚C), a rate faster than either the national or global averages. Temperatures have increased faster during the winter (1.7˚F) and spring (1.8˚F), and overnight low temperatures have increased at a greater rate than daytime high temperatures. Both of these are consistent with trends throughout the Great Lakes region. Seven of the region’s ten warmest years on record have occurred since 2000. Average annual daily high temperatures in Northeast Ohio are projected to increase by 5.7-10.8˚F by 2100, respectively, under low and high emissions scenarios. By the end of the century, the region may average 41-82 days per year with a temperatures above 90˚F, up from just 6-7 days currently. If temperatures rise by 7.2˚F (4˚C), heat-related mortality could increase 17-fold in the region.
Water and Extreme Precipitation
Because warmer air holds more water, Northeast Ohio has seen increases in both average precipitation and extreme precipitation events over the past several decades. Since 1950, annual precipitation has increased by 9.4% (7.1 inches), with the greatest increases occurring during the fall (17.9). Much of this change has been due to an increase in the frequency and intensity of extreme precipitation events. From 1958-2016, the amount of precipitation falling during these events has increased by 42% in the Midwest. The precipitation falling during these extreme downpours may increase by another 40% through the end of the century.
Climatic change is already taking a toll on the health of Lake Erie. Higher winter temperatures have halved ice cover on the Great Lakes since the 1970s, and this decrease will only accelerate in the coming decades. Increases in surface water temperatures and extreme rainfall have also contributed to the development of harmful algal blooms (HABs), which have plagued Lake Erie each summer since 2002. Research suggests that climate change may double the frequency and intensity of these HABs, even with significant reductions in phosphorus runoff.
Air Quality and Public Health
Climate change may also degrade air quality in Northeast Ohio. The warm, calm summer days that foster ground-level O3 formation have become more common due to climate change. This trend will continue in the coming decades. According to the U.S. Environmental Protection Agency, O3 levels may increase in Northeast Ohio by 3-5 parts per billion (ppb) by 2030. The public health impacts of this increase could be substantial; according to one study, a long-term, 3 ppb increase in O3 levels is equivalent to smoking for 29 years or aging three years.