The hallmark of good science is successful prediction of the outcome of experiments and observations that have yet to be made. The hypothesis, that human activities are warming the Earth, does precisely that.
In 1990, the first report from the Intergovernmental Panel on Climate Change (IPCC) predicted that “business as usual” would “result in a likely increase in global mean temperature of about 1°C above the present value by 2025”. Data from Our World in Data shows that the temperature in 2025 was 0.91°C above the 1985-1995 average.
A more shocking example is that scientists working for oil-major, Exxon, predicted in 1982 that global temperatures would rise by about 1.1 °C between 1980 and 2025. That’s exactly what happened (2025 was 1.08 °C above the 1975-1985 average). To their shame, Exxon (and then ExxonMobil) supressed this clear and accurate understanding of climate change until it was uncovered by journalists in 2015.
In contrast, alternate explanations of climate change fail this test. For example, a paper written in 1997 successfully linked sunspot cycle lengths to warming. However, since 1997, there have been two further sunspot cycles. The average temperature in 1996-2008 was 1.2 °C warmer than the sunspot-prediction and, for 2018-2019, temperatures were 0.8 °C warmer than predicted. Useless!