The Earth’s climate is a complex and ever-changing system. It is shaped by the balance of incoming and outgoing energy from the Sun. This energy is reflected by bright surfaces such as ice and clouds, absorbed by the atmosphere and oceans, and re-emitted in the form of heat (longwave or infrared radiation). Changes to this energy flow have the potential to alter the planet’s overall temperature. These changes are called climate change.
Scientists have concluded that human activities such as fossil fuel burning, deforestation and land-use changes are causing the concentration of heat-trapping greenhouse gases in the atmosphere to rise, contributing to global warming. They have also found that the changes in atmospheric and ocean circulation are changing regional weather patterns, including changing the amount and timing of seasonal rainfall.
These changes are already being felt around the world: Arctic summer sea ice has been shrinking for years, glaciers and ice sheets on land have been melting faster, and temperatures have risen. Sea levels are rising, rivers and lakes are warming and drying up, and heat waves are becoming more intense. And we’re just getting started: scientists predict that climate change will continue to worsen in the coming decades.
In 2022, NASA scientists mapped almost 10 billion individual trees in Africa’s dense tropical forests, the largest carbon storage source outside of Europe’s dense forests. This data helps track the movement of climate-changing greenhouse gases across the continent and provide a way for scientists to monitor emissions and measure changes in the region.
This information is vital for determining how much greenhouse gases we emit and the impact of our actions on the Earth’s climate. Luckily, we can use this information to make changes and reduce our emissions.
The most important thing to remember is that Climate Change isn’t just a threat for the future – it’s happening now. We’re already experiencing the impacts: climate-related deaths are increasing, droughts and floods are becoming more frequent, and some species are struggling to find food and water in a changing environment.
Some living things respond to climate change: for example, some plants are blooming earlier and some animals are expanding their geographic ranges, but this response is usually too little too late to offset the damage. In addition, invasive species are spreading as their habitats shrink and are more likely to thrive in warmer conditions.
Scientists say that even if we manage to keep the global average temperature below 1.5 degrees Celsius, many natural hazards will persist, and ecosystems will be stressed. They warn that beyond 1.5 degrees, there are cliffs of species extinction, irreversible loss of polar ice and sea level rise of several meters.
The IPCC report concludes that it is “extremely likely” that more than half of the observed increase in global average surface air temperature since 1951 was caused by humans, with a best estimate of 95%. But it’s also clear that we can take action to limit the damage, and that we must do so quickly.