The facts are these: The climate of our planet is changing at a pace unlike anything seen in the natural fluctuations traced across geological records, and scientists have overwhelmingly traced this global warming trend to human activity.
Unless you’re a supercomputer, you’ll find it virtually impossible to keep an eye on every single indicator of climate change. Here are a few that scientists use to monitor the planet:
For more, check out this story on how we know climate change is happening—and that humans are causing it.
CO2 in the atmosphere
- Measured in: DO-D4 (“abnormally dry” to “exceptional drought”)
- Where to check: U.S. Drought Monitor
- The latest: 12.2 percent of the United States is currently impacted by drought, with 0.34 percent of the United States currently in a D-3 “extreme drought.” 89 million people in the United States are currently impacted.
- Why it matters: Drought—a prolonged period of dry weather—occurs when there’s an imbalance between evaporation and precipitation. It’s the real-world consequence of rising temperatures and can have devastating impacts on human health, food availability, animals, and soil.
- What will help: It’s impossible to directly prevent a drought, especially since it’s closely tied to shorter-term climate oscillations, as well. Water conservation and planning are the only ways to mitigate drought impacts. However, more balanced precipitation and evaporation make drought less likely. You guessed it—greenhouse gas reduction will help in the long term.
- Who rang the alarm: Meteorological drought (Palmer, 1965)
- Learn more: Historical Palmer Drought Indices (NOAA); National Drought Mitigation Center (University of Nebraska – Lincoln); Drought.gov (National Integrated Drought Information System)
Global Mean Sea Level (GMSL)
- Measured in: mm (millimeters) anomaly
- Where to check: NASA
- The latest: The current rate of change of the global mean sea level is a rise of 3.4 mm/year.
- Why it matters: Melting ice and a warming ocean mean more water and a rising sea level. Though the global sea level is also affected by short-term climate phenomena and geographic factors, it is closely linked to temperature. Sea levels rose consistently throughout the 20th century, leaving coastal regions more vulnerable to flooding, storm surges, and salt water seeping into freshwater aquifers and affecting plant and animal habitats.
- What will help: Three words: Reduce greenhouse gases.
- Who rang the alarm: Ice melt, sea level rise, and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2°C global warming could be dangerous (Hansen et al.)
- Learn more: Is Sea Level Rising? (National Ocean Service/NOAA); CU Sea Level Research Group (University of Colorado – Boulder); Global Average Absolute Sea Level Change, 1880-2014 (Open Knowledge International)
Sea Surface Temperature (SST)
- Measured in: °C (degrees Celsius) anomaly
- Where to check: NOAA/NCEI Extended Reconstructed Sea Surface Temperature (ESST)
- The latest: The average SST in 2016 was the warmest ever recorded, averaging 0.75: °C than last century’s average.
- Why it matters: Our oceans absorb heat, and the more they absorb, the warmer they get. This doesn’t just affect marine life, disrupting fish populations, fueling algal blooms, and killing coral. Higher sea surface temperatures also create more atmospheric water vapor. In turn, more water vapor drives a higher risk of extreme weather events, droughts, and disrupted storm patterns.
- What will help: The less heat the oceans must absorb, the cooler they’ll be. There’s only one way to accomplish that: Reduce greenhouse gases.
- Who rang the alarm: Temporal coherence in North Pacific sea-surface temperature patterns (Namias and Born, 1970)
- Learn more: Sea Surface Temperature Image Archive (Rutgers University); MODIS Satellite Sea Temperature (NASA); Sea Surface Temperature Trends (U.S. EPA)
Arctic and Antarctic Sea Ice Extent
- Measured in: sq km (square kilometers) in which there is at least 15 percent ice
- Where to check: Sea Ice Index (National Snow and Ice Data Center)
- The latest: In January 2017, the Arctic sea ice extent was 13.4 million sq km—1.3 million sq kim less than the 1981-2010 mean for January. The Antarctic sea ice extent was 4.0 million sq km—0.6 million sq km less than the 1981-2010 mean for January.
- Why it matters: The polar ice caps have existed for millions of years. Not only are they a reliable indicator of climate change, but they reflect sunlight. That high albedo (reflectivity) helps deflect solar radiation, cooling off Earth. As the ice caps shrink, they stop cooling the poles. The less ice at the poles, the faster global warming will occur. In addition, the ice caps interact with animals (they’re habitat for everything from polar bears to penguins) and influence far-away weather. And as ice caps melt, they increase sea levels around the world.
- What will help: You know the score by now. The fewer greenhouse gases, the more protected our polar ice caps.
- Who rang the alarm: West Antarctic ice sheet and CO2 greenhouse effect: a threat of disaster (Mercer)
- Learn more: Arctic Sea Ice Minimum (NASA); Current State of the Sea Ice Cover (NASA); PIOMAS Arctic Sea Ice Volume Reanalysis (Polar Science Center)
source: popsci.com By Erin Blakemor