One dataset · Three perspectives · 1980–2019

A warmer
normal.

A cooler year can interrupt a warming trend without reversing it. Forty years of NASA temperature data show why the bigger picture matters.

GLOBAL LAND–OCEAN TEMPERATURE / NASA GISTEMP v4
All anomalies are relative to the 1951–1980 average.

40 years Four complete decades
+0.557°C 2010s mean minus 1980s mean
19 of 20 Years ≥ +0.50°C in 2000–2019
01 / LINE

The direction survives the dips.

Annual global temperature anomaly (°C), 1980–2019. Every point is labeled with its value.

Annual global temperature anomalies, 1980–2019, relative to 1951–1980 Temperature anomaly (°C) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0.26 0.32 0.14 0.31 0.16 0.12 0.18 0.32 0.39 0.27 0.45 0.41 0.22 0.23 0.31 0.45 0.33 0.47 0.61 0.38 0.39 0.53 0.63 0.62 0.53 0.68 0.64 0.66 0.54 0.66 0.72 0.61 0.65 0.67 0.75 0.89 1.01 0.91 0.85 0.98 1980 1985 1990 1995 2000 2005 2010 2015 2019 Year

What it shows. The anomaly rises from +0.26°C in 1980 to +0.98°C in 2019. The record includes declines, such as 1998 to 1999, but later years sit much higher overall.

Why this chart works. Connecting consecutive years preserves the sequence, revealing both the long-term direction and short-term variation.

02 / COLUMN

Each decade starts from a higher level.

Mean of the 10 annual anomalies in each decade. The vertical scale starts at zero.

Average temperature anomaly by complete decade, 1980s through 2010s Mean temperature anomaly (°C) 0.0 0.2 0.4 0.6 0.8 1.0 +0.247°C +0.386°C +0.588°C +0.804°C 1980–1989 1990–1999 2000–2009 2010–2019 Decade · 10 annual observations each

What it shows. Decadal means increase from +0.247°C in the 1980s to +0.804°C in the 2010s, a rise of 0.557°C. Every decade is warmer than the one before it.

Why this chart works. Equal ten-year groups reduce the visual distraction of individual years and make the size of each decade’s average easy to compare.

03 / DOUGHNUT

What was unusual becomes common.

Share of years reaching a +0.50°C annual anomaly, across two equal 20-year periods.

Share of years at or above a +0.50°C anomaly: 5 percent in 1980–1999 versus 95 percent in 2000–2019 Years with annual anomalies ≥ +0.50°C 5% 1 of 20 years 1980–1999 Below +0.50°C: 19 years 95% 19 of 20 years 2000–2019 Below +0.50°C: 1 year Orange: at or above +0.50°C · Gray: below +0.50°C

What it shows. Only 1 of 20 years reached +0.50°C in 1980–1999, compared with 19 of 20 in 2000–2019. Warmer conditions become persistent within this record.

Why this chart works. Two identically sized rings compare proportions with equal denominators. Both percentages and counts are printed inside the chart.

+0.50°C is a descriptive threshold chosen for this comparison, not a climate-policy target. These anomalies use a 1951–1980 baseline, not a preindustrial baseline.

The argument

Read the pattern, not just the latest dip.

The annual record shows variation; decade averages show a sustained rise; the proportion comparison shows how common warmer years became. Together, they support a warming trend across 1980–2019. These charts describe temperature change; they do not establish its causes.

The evidence

Original data used in all three charts

A 40-row subset of NASA’s annual J–D column. Source values in hundredths of a degree were divided by 100. No years within 1980–2019 were omitted. The four tables continue chronologically from left to right.

1980–1989
Year Anomaly (°C)
1980+0.26
1981+0.32
1982+0.14
1983+0.31
1984+0.16
1985+0.12
1986+0.18
1987+0.32
1988+0.39
1989+0.27
1990–1999
Year Anomaly (°C)
1990+0.45
1991+0.41
1992+0.22
1993+0.23
1994+0.31
1995+0.45
1996+0.33
1997+0.47
1998+0.61
1999+0.38
2000–2009
Year Anomaly (°C)
2000+0.39
2001+0.53
2002+0.63
2003+0.62
2004+0.53
2005+0.68
2006+0.64
2007+0.66
2008+0.54
2009+0.66
2010–2019
Year Anomaly (°C)
2010+0.72
2011+0.61
2012+0.65
2013+0.67
2014+0.75
2015+0.89
2016+1.01
2017+0.91
2018+0.85
2019+0.98

Calculations: decade mean = sum of 10 annual anomalies ÷ 10; percentage = years at or above +0.50°C ÷ 20 × 100. Annual values retain NASA’s two-decimal precision; decade means are shown to three decimals. Historical values can be revised. The scope ends in 2019 to compare four complete decades; this is not a report of the latest temperature.