Checkpoint Science Practice Test 2026 – All-In-One Guide to Master Your Exams!

Rising global temperatures reflect a long-term warming of the climate. Over many decades, measurements from weather stations, ships, buoys, and satellites show a clear upward trend in Earth's average surface temperature. This sustained warming is the most direct and widely observed sign that the climate system is changing, driven in part by higher greenhouse gas concentrations trapping more heat. Other options don’t fit as well: volcanic activity can cool or heat the climate only in short bursts and isn’t a persistent trend; ozone depletion concerns atmospheric chemistry and UV exposure rather than long-term heat balance; and a decrease in sea levels would contradict the actual pattern, since sea levels are rising due to warming and ice melt.