What is climate change? Climate change refers to long-term shifts in temperatures and weather patterns. Such shifts can be natural, due to changes in solar activity, or major volcanic eruptions. But since the 1800s, the main cause of climate change has been human activities, primarily due to the burning of fossil fuels such as coal, oil and gas. Burning fossil fuels creates greenhouse gas emissions that act like a blanket enveloping the Earth, trapping the sun’s heat and raising temperatures. The main greenhouse gases causing climate change include carbon dioxide and methane. These gases are released when using gasoline to drive a car or coal to heat a building, for example. Land clearing and deforestation can also release carbon dioxide.

Agriculture and oil and gas operations are the main sources of methane emissions. Energy, industry, transport, buildings, agriculture and land use are the main sectors causing greenhouse gas emissions. Humans are responsible for global warming Climatologists have shown that humans are responsible for virtually all of the global warming over the past 200 years. Human activities, as described above, are producing greenhouse gas emissions that are warming the planet faster than at any time in the last two thousand years. The Earth’s average surface temperature is now about 1.2°C higher than it was in the late 1800s (before the Industrial Revolution) and higher than at any time in the last 100,000 years. The last decade (2011-2020) was the warmest on record, and each of the last four decades has been warmer than any previous decade since 1850. Many people think that climate change basically means rising temperatures. But rising temperatures are only the beginning of the story. Because the Earth is a system where everything is interconnected, changes in one area can affect changes in all others. The impacts of climate change now include, but are not limited to, intense droughts, water shortages, severe fires, rising sea levels, floods, melting polar ice, catastrophic storms, and decreased biodiversity. People experience climate change in different ways Climate change can affect our health, ability to grow food, shelter, safety and work.

Some of us are already more vulnerable to climate impacts, such as those living in small island states and other developing countries. Conditions such as rising sea levels and saltwater intrusion have reached such levels that entire communities have been forced to relocate, and prolonged droughts are putting people at risk of starvation. The number of people displaced by weather events is expected to increase in the future. Every rise in global temperature matters In a series of UN reports, thousands of scientists and government experts have agreed that limiting global temperature rise to 1.5°C will help avoid the worst impacts of climate change and maintain a habitable climate. However, current policymakers point to a temperature rise of 3°C by the end of the century. The emissions that cause climate change come from every corner of the world and affect everyone, but some countries produce significantly more emissions than others. The seven largest emitters (China, the United States, India, the European Union, Indonesia, the Russian Federation and Brazil) produced approximately half of all global greenhouse gas emissions in 2020. Everyone must take action to combat climate change, but the people and countries that create most of the problem have the greatest responsibility for taking action first.

We face a huge challenge, but we already know many solutions. Many solutions to climate change can bring economic benefits, improve our lives and protect the environment. We also have global frameworks and agreements to guide progress, such as the Sustainable Development Goals, the UN Framework Convention on Climate Change and the Paris Agreement. The three broad categories of action include: reducing emissions, adapting to climate impacts, and financing necessary adjustments. Shifting energy systems away from fossil fuels and towards renewables such as solar or wind will reduce the emissions that cause climate change. But we need to act now. While more countries are committing to achieving net-zero emissions by 2050, emissions must be halved by 2030 to keep warming below 1.5°C. To achieve this, the use of coal, oil and gas must be significantly reduced: more than two-thirds of today’s proven fossil fuel reserves must remain in the ground by 2050 to prevent catastrophic levels of climate change.

Adapting to the impacts of climate change protects people, homes, businesses, livelihoods, infrastructure and natural ecosystems. It covers current impacts and those likely in the future. Adaptation will be needed everywhere, but the need now is to first help the most vulnerable people who have the fewest resources to cope with climate hazards. Profitability can be high. For example, early warning systems for disasters save lives and property and can provide benefits up to 10 times the initial cost. We can pay the bill now or pay dearly in the future Action to combat climate change requires significant financial investment from governments and businesses. But inaction on climate comes at a much higher cost. One important step is fulfilling the commitment of industrialized countries to provide $100 billion a year to developing countries so they can adapt and move toward greener economies.