Frequently Asked Questions
Doesn't Earth's climate change on its own? Why are we worried about climate change?
Yes, the climate has changed on its own over Earth's history, going through periods of ice ages and extreme heat. There was even a time where there was enough carbon dioxide released to double the concentration in the atmosphere causing mass migrations and extinctions. However, it has been shown that human activities have increased levels of carbon dioxide and other greenhouse gases in the atmosphere, leading to changes much faster than it would naturally occur. Read more about the history of Earth's climate and how scientists are able to understand historic climates here.
Can't changes in how much energy comes from the Sun affect temperatures on Earth? Could this be why the climate is changing?
The Sun does goes periods of dimming and brightening called solar cycles; these solar cycles last about 11 years. Despite these changes in incoming radiation, the warming we are experiencing on Earth is far too rapid to be caused by the Sun. Additionally, solar radiation has decreased slightly over the last 40 years. Read more about solar cycles and climate change here.
What about changes in the Earth's orbit?
Earth's orbit, the tilt of Earth's axis, and where the axis is pointed goes through cycles called Milankovitch cycles. This can affect Earth's climate and how much solar radiation reaches the surface. The cycles, though, last between 26,000 and 100,000 years and cannot explain the rapid warming experienced since the Industrial Revolution. Read more about Milankovitch cycles and climate change here.
What if we find out 50 years later that humans are not affecting the climate? Why should we still invest in renewable energy?
There is always the possibility that humans are not making as big of an impact on the climate as is currently believed by most climatologists, but there are still many reasons to invest in renewable energy. First, we know that coal and natural gas plants emit a lot of air and water pollution which can cause breathing problems, cancer, premature death, and other health problems. Renewable energy can help eliminate this pollution. Next, coal mines, and oil and natural gas reserves can be exhausted, but that is not an issue with renewable energy. Introducing renewable energy technologies can create thousands of jobs as these new facilities will need to be designed, built, and maintained. It would also create jobs for people in sales, logistics, and financial, legal, and consulting services. Read more on the benefits of renewable energy here.
Is this a useless fight? Is it too late to reverse the damage or prevent more?
It would take many years for the warming to stop even if we stopped emitting greenhouse gases immediately because the Earth takes awhile to respond to these changes; that's why we didn't notice the warming until recent decades. All hope is not lost though. We can still slow the rate of warming so it is easier to adapt to these changes over the next several decades. Read more here.
Should we try counter-measures to cool the planet?
The most popular idea to cool the planet is by spraying sulfur dioxide into the stratosphere (the second layer of the atmosphere above the surface) and creating artificial clouds to reflect solar radiation back out to space, similar to what volcanoes already do. Thankfully, violent volcano eruptions causing the climate to change for long periods of time do not occur that often. Plus we would have more control over the concentration and location. Problems could arise if there is too much sulfur dioxide in the stratosphere or if the program were to end abruptly due to situations such as lack of funding or loss of public support. An abrupt end could lead to warming that is too quick to adapt to by humans, animals, and plants. Read more about this here.