Is climate change real and if so, what causes it?
Executive summary
Climate change is real: a broad body of observational evidence shows Earth's average surface temperature and many climate indicators have risen in recent decades, and leading scientific assessments conclude human activities — especially burning fossil fuels that emit greenhouse gases — are the primary driver of that recent warming [1] [2] [3]. While nearly all major scientific organizations concur on the basic facts, debate persists in public fora over precise metrics (for example, how to summarize "consensus" as a single percentage) and the pace and scale of future impacts [4] [5].
1. The empirical case: what the measurements show
Multiple long-term observational datasets and syntheses assembled by agencies and review bodies document rising global mean temperatures, warming oceans, shrinking ice, changing coastlines and shifts in extreme weather patterns, and these trends form the backbone of the claim that climate is changing now [1] [2] [6].
2. Attribution: why scientists conclude humans are the main cause
Attribution studies synthesize physics, observations and climate models to separate natural variability from forced changes, and mainstream scientific assessments conclude that the dominant cause of the observed warming since the mid-20th century is anthropogenic greenhouse gas emissions — principally carbon dioxide from fossil-fuel combustion — a conclusion reiterated by NASA, NOAA and the IPCC and endorsed by national science academies [1] [2] [7].
3. The scientific consensus — strong but sometimes misstated
A wide range of peer-reviewed analyses and statements from professional societies report overwhelming agreement among climate scientists that humans are causing recent warming; different methods yield slightly different headline numbers (commonly cited figures are ~95–99% among actively publishing climate researchers), and some critics contend simpler summaries such as "97%" can be misleading without context about sampling and definitions [8] [9] [10] [5].
4. Where legitimate uncertainty remains
Science is clear about the direction of change and primary causes, but uncertainty remains about the magnitude and timing of specific regional impacts, the sensitivity of the climate system to added greenhouse gases, and the most effective policy and technological pathways to limit warming — uncertainties that drive active research and policy debate rather than undermine the core attribution [4] [6].
5. Politics, perception and competing agendas
Public perception lags scientific consensus: surveys show large political and demographic divides in what people believe scientists agree on, and those divides influence policy and communication strategies [11]. Fossil-fuel interests, some political actors and commentators have historically emphasized uncertainty to slow or block policy responses, a dynamic critics document even as the scientific community grows more certain about anthropogenic causes [4] [8]. Conversely, research shows that clear messaging about the scientific consensus can increase public understanding and support for action across diverse audiences [12].
6. The practical takeaway
The evidence establishes that global warming and associated climate changes are happening now and that human greenhouse-gas emissions are the primary cause; recognizing where science is robust (direction and human attribution) and where active research continues (regional impacts, socio-economic pathways and precise sensitivity estimates) is essential for informed policy and public discussion [1] [2] [6]. Statements summarizing "consensus" are useful shorthand but should be read with attention to definitions and methods; critiques about exact percentages point to methodological nuance, not to refutation of the fundamental scientific conclusion that human actions are driving recent climate change [5] [8].