Climate Change is a complex, global phenomenon affecting all life on Earth. It is driven by a combination of natural and human factors, including changes in the intensity of the Sun’s radiation, volcanic eruptions, variations in Earth’s orbit and shifts in naturally occurring concentrations of greenhouse gases. Geological records show that the Earth’s climate has changed many times in the past, but today the changes are happening much faster than in the past and can’t be explained by natural causes alone.
Increasing greenhouse gas emissions are making the Earth warmer. This is because the gases, such as carbon dioxide (CO2), nitrous oxides and fluorinated chemicals, are absorbed by the atmosphere and ocean, which warms it up and radiates heat back into space. The result is a global warming effect that’s been measured in the air, water and land. Since the mid-20th century, the global average surface temperature has increased by about 1.1°C. Each of the past four decades has been warmer than any previous decade in the modern record.
These warming trends are the main driver of Climate Change, but it’s important to remember that Climate Change is about more than just warmer temperatures. It’s also about changes in weather patterns like drought and flooding, which can harm people, wildlife and places that we value. These effects are called ‘stress multipliers’ because they make existing problems worse. They are especially serious for those who contribute least to climate change but are most affected by it, and for people in poorer countries and communities around the world.
The most important thing to understand is that we can’t predict exactly what will happen in the future. But we know what’s driving it, and that means we can take action now to limit the damage.
A growing body of scientific evidence supports the view that human activity is responsible for changing the climate. This evidence includes a range of observations and measurements, as well as predictions based on computer simulations of the Earth’s climate system.
The key finding is that human activities have altered the Earth’s energy balance towards warming, and the dominant factor is increasing levels of greenhouse gases, particularly carbon dioxide. Other factors influencing the climate system include changes to land use, such as clearing forests, which can reduce the amount of CO2 stored by trees.
The climate changes we are seeing are unprecedented in the history of our planet. They are causing significant impacts on the environment and on society, with implications for health, food security, economics, water supplies, biodiversity and quality of life. They are happening faster than in the past, and will continue to accelerate over the next few decades. This is a critical moment for the global community, and a true paradigm-shift is needed. A climate change response that’s informed by science is urgently needed to limit the scale of future impacts and minimise the risks. Achieving this will require a global partnership of all nations, states and regions working together.