This is Caldo.
Your knowledge hub on climate change and sustainable development.
In Italian, caldo means “hot”. Like our planet today.
Caldo is rooted in three principles.
Science.
This is the starting point, no matter what.
Awareness.
Make the science of climate change and sustainable development accessible to everyone.
Independence.
Nobody pays me to write - alias I write what I think.
Scroll down to learn the basics of climate change, or jump straight to the latest articles.
What is climate change?
The Earth's average temperature is about 1.5°C but has been much higher and lower in the past. There are natural fluctuations in the climate but scientists say temperatures are now rising faster than at many other times. First though: are climate and weather the same?
Weather describes the conditions outside right now in a specific place. For example, if you see that it’s raining, that’s a way to describe today’s weather. Rain, snow, wind, hurricanes, tornadoes — these are all weather events.
Climate, on the other hand, is more than few sunny days. It describes the weather conditions that are expected in a region at a particular time of the year. Is it usually rainy or usually dry? Is it typically hot or cold? A region’s climate is determined by observing its weather over a period of generally 30 years.
Climate change describes a change in the average conditions — such as temperature and rainfall — in a region over a long period of time.
We live in a greenhouse.
The analogy is simple: in a greenhouse, the solar energy can get in, but the heat cannot escape back out again because of the glass panels. It works the same with the atmosphere. About half the light reaching Earth's atmosphere passes through the air and clouds to the surface, where it is absorbed and then radiated upward in the form of infrared heat. About 90% of this heat is then absorbed by the greenhouse gases (GHG) and radiated back toward the surface. The natural greenhouse gas effect is essential for survival: without it, the Earth would be about 30°C colder and hostile to life.
Now, the problem is that human activities — such as burning fuel to power factories, cars and buses — are enhancing the natural greenhouse effect. These changes cause the atmosphere to trap more heat than it used to, leading to a warmer Earth. This is the crux of what we call anthropogenic (or human-induced) climate change.
What are greenhouse gases?
Top on the list is carbon dioxide (CO2) due to both its relative abundance and long atmospheric lifetime, estimated between 300 and 1,000 years. Most anthropogenic emissions of CO2 come from burning fossil fuels. When carbon-absorbing forests are cut down or burned, that stored carbon is released, contributing to global warming.
Other greenhouse gases like methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride are also released through human activities but in a much smaller scale.
2020 GHG emissions by gas
Lapse of time in atmosphere
Where do global GHG emission come from?
Energy is responsible for almost three-fourths of global greenhouse gas emissions. The majority of this energy is used for buildings, industry and transport.
Is there any evidence of warming?
Carbon dioxide.
CO2 levels in the air are at their highest since 800,000 years.
Global temperature.
Nineteen of the warmest years have occurred since 2000.
Arctic ice.
In 2012, Arctic summer sea ice shrank to the lowest extent on record.
Sea level.
Global average sea level has risen nearly 178 mm over the past 100 years.
Source: NOAA (2018)
How much will temperatures rise in future?
Most simulations suggest that the global surface temperature increase between 1850 and 2100 is likely to exceed 1.5°C. If the current warming trend continues, temperatures could rise 3-5°C by end of the century. A 2°C increase had long been regarded as the gateway to dangerous warming. More recently, scientists and policymakers have argued that limiting temperature rises to 1.5C is safer.
The United Nations is leading a political effort to stabilize greenhouse gas emissions. But even if we now cut GHG emissions dramatically, scientists say the effects will continue. Indeed, it takes centuries to remove carbon dioxide from the atmosphere.
Will this change affect me?
Yes, although it is uncertain how great the impact will be.
Climate change is expected to increase the frequency of extreme weather events – even if linking any single event to global warming is complicated. It could cause fresh water shortages, dramatically alter our ability to produce food, and increase the number of deaths from floods, storms and heatwaves.
Will climate change impact all people equally?
No. Poorer countries, which are least equipped to deal with rapid change, could suffer the most. The 1˚C temperature increase experienced so far has influenced the shifts in the distribution of plant and animal species, decreases in crop yields and more frequent wildfires. The cost of this shift is heavier for poorer countries which dispose of less resources and are least equipped to adapt to rapid change. Therefore, climate change can be a poverty multiplier acting on two dimensions.