Tuesday marks the start of the summer solstice, or – as it has come to be known – Show Your Stripes Day.

Show Your Stripes Day was created five years ago by Dr. Ed Hawkins, a climate scientist at the University of Reading in the United Kingdom. Hawkins wanted to create a simple and universal way for everyone, regardless of education, to view and understand how average temperature has changed over time.

Each stripe in the graphic below represents the average temperature for a specific year relative to the 20th-century average. A blue stripe indicates a colder than average year while a red stripe represents a warmer than average year.

For sites with more than 100 years of temperature data we can analyze and begin to understand how the Earth, our states and our communities are warming.

Iowa, for example, has experienced sporadic below average temperature years over the past 140 years. A few of the hottest years ever stick out clearly during the 30s, but if you look a little closer at the past 10-20 years, you’ll notice more warmth than cold.

Of the top 10 hottest years ever in Iowa, four were during the 1930s, but 2012 and 2016 also make the list. These years were especially dry here in Iowa which allowed for temperatures to warm even more. However, despite a wetter year, Iowa has still experienced above average temperatures.

Globally, there is a much different story.

While Iowa was experiencing some of its hottest years on record during the 1930s, globally these were some of the coldest years on record. However, as time has gone on and greenhouse gas emissions have started to rise at an alarming rate, so has the temperature of the Earth.

These are the 10 hottest years on the globe:

All 10 of them occurred after the turn of the new century. What that tells us is that not only is every year consistently above-average but year after year we continue to experience a top-ten hottest year.

We know the consequences of a warming Earth and Hawkins reminds us that those consequences won’t get better as long as we continue what we’re doing as a society.

“As the planet warms the consequences, just get worse and worse and worse until we stop adding greenhouse gases to the atmosphere. And so that means, increases in extreme weather, increases in temperature changes in rainfall patterns so droughts in some areas, increased rainfall in other areas at sea levels are going to continue to rise for centuries. And we’re already seeing the effects on the marine environment around our coasts so coral reefs and fisheries, for example, and many people rely on those on the ecosystems in the ocean to survive,” said Hawkins.

While the current warmth we feel now on Earth is nothing like the warmth the Earth experienced millions of years ago, humans were not part of the Earth during that time.