The climate system on Earth responds to the sun’s energy and the amount of greenhouse gases in the atmosphere. Those gases act as a kind of heat shield, helping to trap energy in the Earth’s surface and keep it from escaping into space as infrared radiation.
Scientists believe that most of the extra energy coming into our planet’s climate system is due to human activities such as deforestation, burning of fossil fuels and agriculture. These activities emit carbon dioxide (CO2) and other “heat-trapping” greenhouse gases into the atmosphere, which in turn traps more heat than would otherwise be there.
Temperatures have been warming since the mid-1800s, based on temperature data from weather stations and other observations. Those measurements, together with other climate-sensitive indicators such as tree rings and ice cores, have led to estimates of global temperatures that are close to the highest they have been at any time in history.
These data have also been corroborated by satellite observations and other methods of measuring temperature changes. These independent sources of information have shown that the planet is getting warmer at a much faster pace than in the past.
As the earth’s temperature increases, we can expect more extreme heat waves and more severe storms. These intense weather events can cause flooding and damage to buildings, crops and other property.
Many people are already seeing changes to the climate, from the loss of sea ice to the increasing frequency of wildfires. The effects are already affecting the lives of billions of people around the world, and will continue to worsen with continued unchecked greenhouse gas emissions.
In addition to causing more frequent, more intense and longer-lasting weather changes, global warming is causing ecosystems to change. As the weather warms, plants and animals are rearranging their geographic ranges to better cope with changing conditions, and some species are adapting by growing or blooming earlier.
Polar bears, for example, have begun to hunt seal pubs and other marine mammals as their food sources become scarcer because of the warming climate. This has reduced the size of polar bear populations and may even lead to their extinction.
The warming is occurring at a rate that is significantly higher than in the past, thanks to our emissions of heat-trapping greenhouse gases. If we don’t limit our emissions, scientists estimate that by the year 2050 we will have exceeded the global average of 1.8 degrees Celsius and by 2100 we could reach 3 to 5 degrees.
There are a number of things that we can do to help slow climate change. For instance, using less energy and water, growing more food and planting more trees are all good ways to reduce your carbon footprint.
We can also support scientific research into the climate and our environment, and learn more about how our behavior affects it. The knowledge we gain from research will enable us to make better decisions in the future.
We can also do our part to avoid the worst impacts of climate disruption, but we’ll need social support before we hit hard limits to our ability to adapt. That’s why we are working on the “Climate Resilience Project,” an effort to help communities around the world prepare for a more climate-disruptive future.