A RENOWNED climate scientist has been jailed for fraudulently claiming half a million dollars in reimbursements from his employer.

Over seven years, Australian Institute of Marine Science senior researcher Daniel Michael Alongi lodged 129 claims for fictitious purchases totalling $553,420.

When police caught up with him in 2015, he told them he had spent the money on rare and antique books.

One book, about Captain James Cook's journeys, cost $15,000.

Alongi, 60, pleaded guilty in Townsville District Court yesterday to defrauding the Federal Government agency.

Commonwealth prosecutor Chris Moore detailed Alongi's "carefully executed" offending, which saw him earn far more than his $4000 a fortnight salary.

"To support the claims he created or modified invoices, receipts and credit card statements, along with drafting fake analysis reports and email trails," he said.