I know you don't need me to tell you it has been a hot July. We've had 10 days with temperatures climbing over 90 degrees and every day so far has been above our historical average high, which was 82 for days earlier in the month and is now 81.

May and June weren't quite as extreme, but we had temperatures climb into the 90s both months and most days were warmer than average.

This comes after an early spring, when we recorded the warmest March in history. The station in Preston measured an average temperature of 48.6 degrees, which broke the previous record of 40.6 degrees set in 1973. All eight stations in southeastern Minnesota set March record highs.

Rochester had nine days in March with record temperatures, two of them into the 80s, and 10 days with the warmest low temperature ever recorded on that date. March 19's low of 62 set the record for the warmest low ever recorded in March for one day. On March 16 and 17, the dew point at Rochester International Airport climbed to 62 degrees. Prior to this year, the earliest 60-degree dew point was April 24 in 1990.

July doesn't have as many record-breaking days, and the month isn't over, so its historical place isn't known yet, but all of us will agree that the heat is unusual. After all, I don't recall anyone ever wishing for high temperatures in the 80s in Minnesota - to cool us down.

Many point to the warm spring and hot summer as proof of global warming. Yet, even though it seems like the heat has gone on forever, the unusual warmth is still a weather condition, not a climatic change that we can be sure is global and historical. There may be places elsewhere in the world with unusually cool weather as weather conditions are always subject to wide swings.

However, global warming does increase the extremes in the weather, making hot days hotter, rainfall and flooding stronger, hurricanes and other storms more powerful and droughts more severe. That seems to be happening more frequently in the United States, the record number of tornadoes this spring and ongoing drought this summer as examples.

We can't judge climate change on how it feels when we walk out the door from our air conditioned rooms. While the hot weather outside our homes today may feel oppressive, we should be more concerned about events, such as the iceberg that recently broke free from Greenland's massive Petermann Glacier. The chunk was more than twice the size of Manhattan in New York.

This is the second chunk that has broken off the glacier since 2010. Although it has no dire consequences, it does point to global warming as a cause.

Still, it's not fair to single out one event as proof because there could well be other causes for that one specific instance.

The bottom line, in taking a wider view, is that there are too many changes taking place to be just coincidence or natural cycles.

Many of those changes are outlined in a lengthy document entitled "State of the Climate in 2011" compiled by the National Oceanic and Atmospheric Administration (NOAA) and released earlier this month. The document is peer-reviewed by 378 scientists from 48 countries around the world.

Although the report acknowledges that specific events, such as La Nina, had an effect on weather in 2011, it also acknowledges that Arctic ice is melting, greenhouse gases are growing and temperature extremes are increasing. Many scientists say this is evidence that human activities are contributing to climate change.

Sure there are skeptics and the next record cold temperature - we will get one of those at some point, just not as often as we used to nor as often as we see record hot temperatures - they will claim global warming is a fraud.

One hot streak or a drought isn't going to prove the skeptics wrong, either, but the body of evidence, compiled by scientists seeking the truth, rather than a political agenda, is compelling. In other words, we can expect more "unusual" weather in the future.

What changes that will force is up in the air. The question is will we just turn up the air conditioning and retreat from the natural world, or will we look at real, permanent changes in our lifestyle to reduce the amount of greenhouse gas?

We've been taught that even if we don't like the weather, there is nothing we can do about it. That may not be true today as we've seen that humankind can influence our weather in ways never thought possible. It will just take a lot of people making the same choices.