Kara Lamb is currently a research scientist at the University of Colorado, Boulder. She graduated from the University of Chicago with a Ph.D. in physics in 2015, where she studied cirrus clouds. Now, she studies how aerosols impact air quality and climate through a combination of field campaigns and laboratory studies. Her current research focuses on aircraft observations that she made over S. Korea in 2016 as part of the NASA Korean-US Air Quality Study (KORUS-AQ). She is passionate about science communication and public outreach, and when she's not doing research she enjoys traveling, playing soccer, and biking in the mountains.
Every human being ever has lived on Earth. There are four rocky planets in our solar system, but Mercury and Venus are too hot for us and Mars is too cold. Even on Earth, some places are colder (Siberia) and some are warmer (the Sahara) than others. If you just look at one place (Chicago!) you know December is likely to be very cold–- and in July you’ll want to cool down at the beach.
These day-to- day changes (weather), and month-to- month changes (seasons) make up the climate. The climate is the state of the Earth, and it is controlled by many factors: how far we are from the Sun, what gases make up the atmosphere, and the way the Earth’s surface reflects sunlight.
Scientists know the climate has often changed in the past. In Chauvet Cave in southern France, the cave walls are covered with charcoal drawings of horses, lions, and rhinoceroses. These beautiful images, shaded and etched to appear almost 3-dimensional, seem ready to leap from the cavern walls. Even more incredibly, the artists who drew them lived over 30,000 years ago. We don’t know much about those artists, but we do know their climate was very different than today's. At the time, the Earth was experiencing the last great Ice Age. Even during the summer in France, the snow never melted.
Because the Earth’s orbit around the Sun gradually changes over thousands of years, we no longer experience the colder climate of our ancestors. In fact, the Earth’s climate has been relatively stable for the past 11,700 years, and human beings have thrived. We developed agriculture, civilization, writing, philosophy, and the scientific method.
Nowadays, scientists study how humans (all 7.6 billion of us) affect the climate. Our lives are much easier than our ancestors’ were, but modern manufacturing, transportation, and agriculture emit gases and particles into the atmosphere and transform the Earth’s surface. Along with natural changes in the Earth and Sun, humans contribute to a changing climate.
When scientists talk about climate change, they speak about averages. The average temperature of the Earth is about 59°F; but that average includes all winters and all summers, everywhere on Earth. During the Ice Age, the average temperature was about 12°F cooler than today. In the next 100 years, scientists predict the Earth’s average temperature will increase by 3 or 4°F. This may not sound like a lot, but it means large changes for the Arctic, rising sea levels, and more extreme weather.
The good news is we keep learning more about the Earth’s climate. Scientists use satellites, weather balloons, planes, and ships to monitor the atmosphere. They look at ice cores, rocks, and tree rings to figure out what the climate was like in the past. This data goes into computer models, which forecast how the climate might change in the future. This knowledge allows us to better understand our world, and how to protect the Earth’s climate for future generations."