In the face of unprecendented occurences of extreme weather, loss of species, and pollution, it is clear that climate change is affecting our planet. We cannot afford to wait any longer to act. This quote from the Earth Day 2013 website outlines the theme for this year’s Earth Day campaign which runs under the motto Climate change has many faces.
As the Earth Day campaign points out, the stories of the impact of climate change are extremely diverse: “A man in the Maldives worried about relocating his family as sea levels rise, a farmer in Kansas struggling to make ends meet as prolonged drought ravages the crops, a fisherman on the Niger River whose nets often come up empty, a child in New Jersey who lost her home to a super-storm, a woman in Bangladesh who can’t get fresh water due to more frequent flooding and cyclones.”
All these tales have one thing in common: They are a story of our impact on planet Earth, but equally of the impact of a changing planet on human’s lives. Our species has become one that is not just living in the natural environment, but is one factor that changes the environment to a level that no other species did before. This is happening to an extent that geologists discuss whether this can be seen as a new geologic era. Nobel Prize laureate Paul Crutzen started promoting the idea of the so-called Anthropocene, a concept that has now left the scientific world and is increasingly entering the public debate regarding issues of global sustainability and humanity’s impact. Anthropocene.info is a project initiated by the International Geosphere-Biosphere Programme (IGBP) that aims to “to help visualize and better understand humanity’s geographic imprint in recent time.” Not only is it important to find better ways of understanding the complex interrelations of humans and their natural environment, to which visualisation can contribute, but also is it important to create a public understanding of issues relating to the challenges connected to global change.
Here is one example of a more challenging view existing knowledge that demonstrates how changing the view can make us rethink the way our natural environment is shaped. According to research by the US National Office of Oceanic and Atmospheric Research, “[t]he strongest hurricanes in the present climate may be upstaged by even more intense hurricanes over the next century as the earth’s climate is warmed by increasing levels of greenhouse gases in the atmosphere. Most hurricanes do not reach their maximum potential intensity before weakening over land or cooler ocean regions. However, those storms that do approach their upper-limit intensity are expected to be slightly stronger in the warmer climate due to the higher sea surface temperatures.”
This is relevant due to the impact of more frequent flooding and cyclones on humans mentioned earlier. So where are these spaces where this is relevant. We know from historic records where there are tropical storm tracks, and the emerging pattern on a normal world map may be familiar to some of us (see here). But what if we change the perspective and focus on the actual areas that have the highest density of tropical storm occurrences. Using the records from 1945 to 2008, this intensity can be turned into quantities which are suitable for visualisation using the gridded cartogram technique. The following map shows a gridded cartogram of tropical storm intensity visualised over land based on a 0.25 degree grid. The larger a grid cell, the more tropical storm activity has there been over the past >60 years, indicating where the most affected areas of tropical cyclones (with a sustained wind speed of ver 40 mp/h) has been and how the climate patterns shape the world in a highly relevant issue of the Anthropocene:

(click for larger version)

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