Climate Change Basics: What We Know, in Plain Words
The Earth is warming, and the main cause is known. With the COP31 climate summit weeks away, here are the facts, the numbers, and what actually helps.
Climate change can feel confusing, with arguments all over social media. But the basic science is well understood and has been for decades. Here is what is known, and what the latest data say.
The greenhouse effect, in 4 steps
Sunlight reaches Earth
Much of it passes through the air and warms the ground and oceans.
The surface gives off heat
Warm ground and water send heat back out toward space.
Some gases trap that heat
Carbon dioxide, methane, and water vapour absorb part of it and send it back down.
The planet stays warm
This natural greenhouse effect is why Earth is livable. Without it, the average temperature would be far below freezing.
The problem is that humans have been adding extra greenhouse gases, mainly by burning coal, oil, and gas, and by clearing forests. More gas traps more heat, so the planet warms.
What the data show
According to the World Meteorological Organization (WMO), the year 2025 was the second or third warmest on record, about 1.43 °C above the 1850 to 1900 average. The years 2015 to 2025 were the 11 hottest years in the record. The three-year average for 2023 to 2025 was about 1.48 °C above the pre-industrial level. The WMO also reports that ocean heat content reached a record high, and that the rate of ocean warming has more than doubled since the period 1960 to 2005.
The 2015 Paris Agreement set a goal of keeping warming well below 2 °C, and trying for 1.5 °C. Note that the 1.5 °C goal refers to a long-term average, not a single year.
What it means for daily life
- More frequent and intense heatwaves.
- Heavier rainfall in some places and stronger droughts in others.
- Rising sea levels, because oceans expand as they warm and ice melts.
- Stress on crops, water supplies, and health, especially for outdoor workers and the elderly.
What helps
Clean energy
Replacing coal and gas with solar, wind, and other low-carbon power is the biggest lever.
Energy efficiency
Better buildings, appliances, and public transport use less energy for the same benefit.
Protecting forests and wetlands
They store large amounts of carbon.
Changing how we move
Walking, cycling, public transport, and electric vehicles cut emissions.
Adapting
Heat action plans, flood defences, and drought-resistant crops protect people from changes already underway.
What you can do
- Use energy wisely at home, and choose efficient appliances.
- Choose public transport, cycling, or carpooling when you can.
- Waste less food, since food waste produces methane.
- Support local trees and green spaces.
- Talk about it. Public support matters for policy.
What is next
The UN climate conference, COP31, is scheduled for 9 to 20 November 2026 in Antalya, Türkiye, where countries will review progress on their climate commitments.
What most people miss
- Weather is not climate. A cold week does not disprove warming, in the same way that one cool day does not end summer.
- Small numbers matter. A global average rise of 1 to 2 degrees sounds tiny, but it shifts weather extremes a lot.
- Individual action helps, but systems matter most. Energy, industry, and transport policies decide the largest cuts.
