Earth Matters

Urban Heat Islands Come with a Cost
The urban heat island effect has been shown to raise the temperature of cities compared to their neighboring rural and semi-rural areas. Research published in May 2017 in Nature Climate Change spells out the cost associated the effect. Economists analyzed 1,692 cities and found that the economic cost of climate change this century could be 2.6 times larger when the heat island effect is accounted for. The costs stem from factors like air pollution, water quality, and energy for cooling.

CO2 Reached Record Highs
In April 2017, the concentration of carbon dioxide in the atmosphere reached (and surpassed) 410 parts per million (ppm) for the first time in recorded history. The milestone measurement was made at the Mauna Loa Observatory in Hawaii, a ground-based station that has collected CO2 data since 1958. (Global, space-based data now supplement those measurements and provide the big-picture view.)

Levels continued to rise, and by the end of May, the monthly average was the highest on record at 409.65 ppm. CO2 concentrations reach an annual peak every May, but the average in May 2017 was well above that of previous years. Check out this graph to see how 2017 has measured up.

Rainfall Reorg
Climate change is likely to affect Earth’s rainfall patterns. Authors of a recent study published in Science Advances used paleoclimate data to examine how rainfall patterns have responded to past climate shifts. These past trends lend evidence to scenarios that could unfold in the future. During the northern hemisphere’s summer, dry areas are likely to become drier and wet areas would be wetter; in the winter, regions of relatively heavy rainfall would expand northward.

Plants Pack a Punch on Precipitation
During photosynthesis, plants release water vapor into the air. This water vapor can ultimately cause clouds to form, which in turn can affect Earth’s energy balance and produce precipitation. A May 2017 study published in Nature Geoscience used global satellite data and a statistical technique to show that as much as 30 percent of the variability in climate and weather patterns can be attributed to plants.

“Hottest” Events on the Rise
Scientists have developed a framework to help determine if an extreme weather events can be attributed to climate change. Using the framework, they show that for 80 percent of areas where observations are available, global warming has increased the chances for (and severity of) “hottest” events—months and days that measure in as the hottest of the year. The research was published May 2017 in Proceedings of the National Academy of Sciences.