How to Calculate Extinction Rate

Extinction Rate Calculator (E/MSY)

Calculation Results

function calculateExtinctionRate() { var species = parseFloat(document.getElementById('totalSpecies').value); var extinctions = parseFloat(document.getElementById('numExtinctions').value); var years = parseFloat(document.getElementById('timePeriod').value); var resultDiv = document.getElementById('extinctionResult'); var emsyText = document.getElementById('emsyValue'); var interpretationText = document.getElementById('interpretation'); if (isNaN(species) || isNaN(extinctions) || isNaN(years) || species <= 0 || years <= 0) { alert("Please enter valid positive numbers for all fields."); return; } // Formula: (Extinctions / (Species * Years)) * 1,000,000 // This yields Extinctions per Million Species-Years (E/MSY) var emsy = (extinctions / (species * years)) * 1000000; var formattedEmsy = emsy.toFixed(4); emsyText.innerHTML = "Extinction Rate: " + formattedEmsy + " E/MSY"; var interpretation = ""; if (emsy 1 && emsy <= 100) { interpretation = "This rate is significantly higher than the background rate, indicating moderate biodiversity stress."; } else { interpretation = "This rate is extremely high (over 100x the background rate), reflecting a mass extinction event scenario or severe local ecosystem collapse."; } interpretationText.innerHTML = interpretation; resultDiv.style.display = "block"; }

Understanding the Extinction Rate

Extinction is a natural biological process, but measuring its speed is critical for conservation biology. To compare modern extinction events with fossil records, scientists use a standardized metric called Extinctions per Million Species-Years (E/MSY).

How to Calculate Extinction Rate (E/MSY)

The calculation requires three primary data points: the size of the group being studied, the number of confirmed extinctions, and the time interval over which those extinctions occurred. The formula is:

E/MSY = (Number of Extinctions / (Total Species × Number of Years)) × 1,000,000

Example Calculation

Imagine a researcher is studying a group of 5,000 tropical beetle species. Over a period of 50 years, they observe that 2 of these species have gone extinct. To find the extinction rate:

• Total Species: 5,000
• Extinctions: 2
• Years: 50

Calculation: (2 / (5,000 × 50)) × 1,000,000 = (2 / 250,000) × 1,000,000 = 8 E/MSY.

The Background Extinction Rate

To understand the severity of a result, scientists compare it to the "background rate." This is the standard rate of extinction observed in the geological record during periods between mass extinctions. Most estimates place the background rate between 0.1 and 1.0 E/MSY. Any value significantly higher than 1.0 suggests that external factors, such as habitat loss, climate change, or pollution, are accelerating species loss.

Why This Metric Matters

The E/MSY metric is powerful because it allows us to compare different groups of organisms. For example, we can compare the extinction rate of mammals (which have fewer species) to insects (which have millions) using a normalized scale. This data is essential for organizations like the IUCN to prioritize conservation efforts and identify ecosystems in crisis.