LAND
Food • Farming • ResilienceClimate-resilient agriculture, soil health and stronger food systems are important adaptation priorities for Pacific communities.
The evidence
76 years. One unmistakable long-term direction.
Tonga's annual national mean surface-temperature anomalies from 1950 to 2025 vary from year to year, but the long-term trend is upward.
+0.1001°Clinear warming trend per decade
+1.1°C2022 - warmest year in the record
-0.5°C1987 - coolest year in the record
+0.488°Cmean anomaly, 2000-2025
The chart is the heart of the story: annual variation remains visible, while the trend line shows the longer-term warming direction.
The central question
Is Tonga getting warmer?
YES.
≈ +0.10°C per decade
Across the complete 1950-2025 analysis window, the ordinary least-squares trend is +0.01001°C per year, equivalent to +0.1001°C per decade.
N = 76 | R² = 0.429 | p = 1.37 × 10⁻¹⁰
Read the chart correctly
What is an anomaly?
A temperature anomaly describes how much warmer or cooler a value is relative to the dataset's reference average.
Negative = cooler than the reference. Zero = at the reference. Positive = warmer than the reference.
The exact baseline period is intentionally not stated here because it was not specified in the verified project analysis report.
The pattern becomes clearer
From near-zero decades to sustained positive anomalies
Decade averages reduce year-to-year noise and reveal the strong shift in the 21st century.
| 1950s | -0.020°C |
| 1960s | -0.120°C |
| 1970s | +0.030°C |
| 1980s | -0.100°C |
| 1990s | 0.000°C |
| 2000s | +0.370°C |
| 2010s | +0.470°C |
| 2020-2025 | +0.717°C* |
*2020-2025 is a partial six-year period, not a complete decade.
Across generations
Climate data connect Tonga's past, present and future.
1950Earlier generations
1980Parents' generation
2000A new century
2025Today's students
2050Next generation
What began as measurements decades ago has become evidence that today's young Tongans can interpret and communicate to their communities.
From numbers to Tonga
The dataset shows the temperature pattern. Wider research explains why climate resilience matters.
These context panels are deliberately separated from the statistical claims above so that the dataviz does not imply that temperature anomalies alone prove every climate impact.
OCEAN
Reefs • Coasts • FisheriesCoastal and marine resilience matters deeply for island communities whose livelihoods and ecosystems are connected to the ocean.
COMMUNITY
People • Knowledge • PreparednessResilience depends on local knowledge, institutions, preparedness and community participation.
FUTURE
Youth • Data • StewardshipData literacy gives young people tools to understand change, communicate evidence and participate in future decisions.
Transparency
Data, method and limitations
Primary dataset: Pacific Community (SPC), DF_CLIMATE_CHANGE (1.0), indicator ST_ANOM - Mean Surface Temperature Anomalies, Tonga. Project analysis window: 1950-2025.
Method: descriptive statistics and ordinary least-squares linear trend. Raw annual values were preserved; the project analysis uses 76 observations. The 2020-2025 block is explicitly treated as a partial period.
Interpretation: the temperature dataset supports statements about temperature anomalies and their trend. Broader statements about agriculture, oceans, communities and resilience are contextual and should be read as separate climate research, not as effects proven by ST_ANOM alone.
Context source register
Evidence beyond the temperature series
- Official competition dataset: Pacific Community (SPC) Pacific Data Hub / .Stat - DF_CLIMATE_CHANGE (1.0), ST_ANOM, Mean Surface Temperature Anomalies, Tonga.
- SPC - Pacific Vision for Adapted Crops and Soil (2025): background for climate-resilient food systems, soil health and adapted crops.
- SPC - Scaling up coastal protection in Tonga: background for coastal-community resilience and adaptation.
- World Bank Climate Change Knowledge Portal - Tonga: broader country climate-risk context only; its separate temperature series is not mixed with the SPC ST_ANOM analysis.
All statistical claims in the charts use the locked SPC ST_ANOM project analysis for 1950-2025. Context sources are separate supporting references.
Tonga National University - School of ICT
Built by a multidisciplinary Tongan team
Project Leaders / Academic Mentors
Semisi Hopoi and Hekisou Fifita
Semisi Hopoi and Hekisou Fifita
Climate Data Analysts
Malia Tonga and Mele Mafi
Malia Tonga and Mele Mafi
Climate Story & Communication Lead
Betty Ahohako
Betty Ahohako
Lead Data Visualisation Developer
Suliasi Talalima
Suliasi Talalima
Data Visualisation & Technical Developer
Sonatane Fa'aui
Sonatane Fa'aui
OUR CHANGING TONGA
76 YEARS OF DATA.
GENERATIONS OF TONGAN EXPERIENCE.
ONE FUTURE WE SHARE.
GENERATIONS OF TONGAN EXPERIENCE.
ONE FUTURE WE SHARE.
The data are numbers.
The story is Tonga's.
The future belongs to the next generation.