The basic science of climate change has been understood for more than a century. What’s changed is the scale, the speed, and the evidence now accumulating in real time about what the warming actually means for people, ecosystems, and the systems we depend on.
Here’s what the science says, clearly and without qualification.
The causes: how we got here
Earth’s climate is regulated by the greenhouse effect, a natural process in which certain gases in the atmosphere, primarily water vapor, CO2, and methane, trap heat from the sun. Without it, the planet’s average temperature would be around -18°C. The greenhouse effect isn’t the problem. The problem is that human activity has dramatically increased the concentration of those gases over the past 200 years.
Since the industrial revolution, CO2 concentrations in the atmosphere have risen from roughly 280 parts per million to over 420 parts per million, a level not seen in at least 800,000 years. The primary driver is the burning of fossil fuels: coal, oil, and natural gas for energy, transportation, and industry. Deforestation is the second largest driver, releasing carbon stored in trees and soil while removing the forests that would otherwise absorb CO2 — which is part of why projects like TIST and Sundarbans mangrove restoration matter so much. Agriculture contributes through methane from livestock and rice cultivation, and nitrous oxide from fertilizers.
The scientific consensus on the human cause of modern climate change is not a matter of debate among climate scientists. It is as well-established as the science of evolution or the age of the universe.
The effects: what we’re already seeing
Climate change is not a future threat. Its effects are already being measured and felt across every region of the planet.
Rising temperatures. The global average surface temperature has increased by approximately 1.1 to 1.2 degrees Celsius above pre-industrial levels. The warming is not uniform: the Arctic is warming roughly four times faster than the global average. The last decade was the warmest on record.
Extreme weather. Warmer temperatures intensify weather systems. Heat waves are more frequent, more severe, and last longer. Rainfall events are more intense, because a warmer atmosphere holds more moisture. Hurricanes and typhoons are strengthening faster and producing more rainfall when they make landfall. Droughts are becoming more persistent in regions that are already dry.
Sea level rise. Ocean levels have risen roughly 20 centimetres since 1900, driven by both the thermal expansion of warming seawater and the melting of ice sheets and glaciers. The rate of rise is accelerating. Hundreds of millions of people live in low-lying coastal areas at risk from flooding and storm surge — including communities near projects like the Sundarbans, where mangrove forests are one of the primary lines of defense.
Ecosystem disruption. Coral reefs, which support roughly a quarter of all marine species, are bleaching at historically unprecedented rates as ocean temperatures rise. Species are shifting their ranges toward the poles and to higher elevations. Seasonal timing is changing: earlier springs, later frosts, shifts in migration and breeding patterns, with cascading effects on food webs.
Who bears the greatest burden
Climate change is not experienced equally. The communities and countries that have contributed the least to greenhouse gas emissions are often the most exposed to the consequences: small island nations facing inundation, sub-Saharan farming communities dealing with shifting rainfall, coastal populations in South and Southeast Asia at risk from cyclones and flooding.
Within countries, lower-income communities face greater exposure to heat, flooding, and air pollution, with fewer resources to adapt. This is part of why Cool Effect focuses on projects in the places most affected: Honduras, India, Kenya and Uganda, the Sundarbans coast of Bangladesh and India. The climate crisis is also a justice issue, and any serious response has to reckon with that.
What the climate requires
The Paris Agreement established a goal of limiting warming to 1.5 degrees Celsius above pre-industrial levels, with a harder upper limit of 2 degrees. To meet the 1.5-degree target, global emissions need to reach net zero by around 2050. That requires cutting emissions from every sector of the economy, at a pace that has no historical precedent.
Carbon credits, used well, are part of that response: they fund real reductions in the places and project types that are hardest to address through other means, and they provide financing for communities on the front lines of the climate crisis. They’re a tool, not a substitute for cutting emissions at the source. But they’re a real one, and they matter.
You can offset your travel footprint in minutes, bring your business into alignment, or simply browse our verified projects and fund the work directly. Every project on Cool Effect has been independently verified to meet rigorous international standards — and 90 percent of every dollar goes straight to the project.
If you want to understand what makes one carbon credit better than another, our buyer’s checklist covers exactly that.