Three foreign countries may be changing their historical weather data to show warming trends, according to a scientist in the field.

Dr. H. Sterling Burnett of the Heartland Institute claims in a story that Australia, Paraguay, and Switzerland have altered their data in an effort to prove global warming is real.

“Switzerland joins a growing list of countries whose temperature measurements have been adjusted to show greater warming than actually measured by its temperature instruments,” Burnett writes. “In previous editions of Climate Change Weekly, I reported weather bureaus in Australia and Paraguay were caught adjusting datasets from their temperature gauges. After the adjustment, the temperatures reported were consistently higher than those actually recorded.”