Paleoclimate Proxy Converter Calculator

Temperature from oxygen isotope ratios (delta18O).

δ18O (‰)

δ18O seawater (‰)

Proxy type (0=Marine, 1=Ice, 2=Cave)

Modern reference temp (°C)

Tab to move between fields

Estimated temperature (°C)

26.06

Temperature anomaly (°C)11.06

δD estimate (‰)-6

Sea level change (m)181.8

Ice volume index (0-100)0

Deuterium excess (‰)10

How to Use This Calculator

Select the Proxy type: 0 for marine carbonates (Shackleton calibration), 1 for ice cores (Jouzel slope), or 2 for speleothems (Kim & O'Neil).
Enter the measured δ18O (‰) value from mass spectrometry — typical marine carbonate values range from −2 to +5 ‰ VPDB.
For marine or speleothem proxies, set δ18O seawater (‰) to account for ice-volume effects on ocean isotope composition.
Enter the Modern reference temp (°C) to compute the Temperature anomaly relative to present.
Read Estimated temperature (°C), Sea level change (m), and Ice volume index to place the sample in a paleoclimate context.

How the result changes with δ18O (‰)

δ18O (‰): Oxygen isotope ratio in per mil. Marine carbonates: -2 to +5 ‰ VPDB. Ice cores: -30 to -60 ‰ VSMOW.
δ18O seawater (‰): Oxygen isotope composition of seawater. Modern ~0 ‰, LGM ~+1.0 ‰ VSMOW.
Proxy type (0=Marine, 1=Ice, 2=Cave): 0=Marine carbonate (Shackleton), 1=Ice core (Jouzel), 2=Speleothem (Kim & O'Neil).
Modern reference temp (°C): Present-day temperature for computing anomaly.

Estimated temperature (°C): Paleotemperature derived from the isotope proxy calibration.
Temperature anomaly (°C): Difference from the modern reference temperature.
δD estimate (‰): Estimated deuterium value from the Global Meteoric Water Line.
Sea level change (m): Approximate sea level change implied by the isotope shift.
Ice volume index (0-100): Relative global ice volume proxy. Higher = more ice.
Deuterium excess (‰): d-excess (δD - 8×δ18O). Indicates moisture source conditions.

Identify Input Parameters
4 parameters
δ18O (‰) = -2, δ18O seawater (‰) = 0, Proxy type (0=Marine, 1=Ice, 2=Cave) = 0, Modern reference temp (°C) = 15 = 4 input(s) provided
Calculate Estimated temperature
Estimated temperature
26.06 = 26.06
Calculate Temperature anomaly
Temperature anomaly
11.06 = 11.06
Calculate δD estimate
δD estimate
-6 = -6