Rio’s Remarkable Record

ASU Climate Data Task Force Report

Earth Day 2000 fast approaches. It’s a sure bet that environmentalists all across this great planet of ours will lament how the promises of the grand Rio Treaty (Framework Convention on Climate Change) largely have been ignored in most real-world applications. Recalling the global warming commitments of the treaty’s signatories and hectoring every politician in sight to "do something about it" undoubtedly will be a major theme of the annual April 22^nd celebration.

Anticipating a Rio remembrance, it may be useful to examine the temperature record for Rio de Janeiro, Brazil, to learn just how severe the greenhouse crisis has become at the world-famous carnival site. Continuous monthly temperature anomalies (deviations from normal) from January 1856 to the near present are available for the Rio area (a 5° latitude by 5° longitude cell) thanks to the United Nations’ Intergovernmental Panel on Climate Change (a product of the Rio Treaty). Just as many might expect, Rio’s temperature record shows warming in this century. But wait, there’s more! Rio’s nearly century-and-a-half-long record provides amazing perspective for those willing to look closer.

Rio’s 144 years of continuous temperature recordings conveniently can be broken into two halves. In the most recent 72 years, the IPCC’s Rio database shows a warming of 1.03°C. However much Leonardo DeCaprio and other Earth Day celebrities might like you to believe this is due to the buildup of greenhouse gases, remember the first half of the record shows a cooling of 0.83°C. Basically, Rio’s temperatures first fell, then recovered. More impressive still, the nine warmest monthly anomalies occurred between 1856 and 1878. The tenth warmest anomaly was in April 1959. The next three (the eleventh through thirteenth warmest anomalies) also occurred between 1856 and 1878.

According to the official UN record of temperatures from the birthplace of the world’s climate change treaty, twelve of the thirteen warmest months in the record occurred over a century ago. One – one – even happened in the 20^th Century, and that years before Leo was born.

Oh, there are many Rio lessons to be preached this Earth Day. But don’t hold your breath waiting to hear the one discerned from Rio’s long and continuous temperature record. Go ahead, exhale some carbon dioxide – green the planet. Happy Earth Day, everyone!

Figure 1. Monthly temperature anomalies (°C) for Rio de Janeiro, 1856-1999.