2040 (MMXL) will be a leap year starting on Sunday of the Gregorian calendar, the 2040th year of the Common Era (CE) and Anno Domini (AD) designations, the 40th year of the 3rd millennium, the 40th year of the 21st century, and the 1st year of the 2040s decade.
|Centuries:||20th century – 21st century – 22nd century|
|Decades:||2010s 2020s 2030s – 2040s – 2050s 2060s 2070s|
|Years:||2037 2038 2039 – 2040 – 2041 2042 2043|
- November 4 – Partial solar eclipse
- 2040 Summer Olympics will be held.
- If the United States had not returned land for bases on Bermuda in 2002, a ninety-nine year lease (signed in 1941) would have expired.
- Climatologists predict that sometime in 2040 the Arctic Ocean will be free of ice, at least during the autumn. (News reports, December 2006).