Global warming – The greenhouse effect

Over the past 800,000 years, carbon dioxide (CO2) and surface temperatures on Earth have remained at structured and reliable levels. In the last century, mainly due to the large use of fossil fuels, atmospheric CO2 levels have exceeded historical levels of over 400 parts per million (ppm). The greenhouse effect is a process through which gases in the atmosphere trap heat from the sun that would otherwise escape into space. This process makes our planet habitable, however, the continuous increase in greenhouse emissions such as CO2 causes extra heat to be trapped and global temperatures to rise. The planet’s surface temperature has risen about 1.1°C since the late 19th century. Most of the warming occurred in the past 40 years and 19 of the 20 warmest years since 1880 have occurred after 2001. 2016 ranks as the warmest year on record and there is a very high chance for 2020 to surpass it.

Effects of climate change

We can already see the negative effects of climate change and with increasing emissions they will only get worse:

Weather: Besides the temperature rise, there are changes in precipitation patterns; heatwaves, floods, droughts and extreme weather events such as hurricanes and tornadoes occur more often and are more widely spread.

Ice: Temperature increase leads to ice melting. The Greenland and Antarctic ice sheets have decreased substantially in mass in the last 30 years, losing on average 150 to 280 billion tons of ice per year. Glaciers around the world such as the Alps, Himalayas, Andes or Rockies are also retreating yearly, and many are at risk of disappearing completely in the next 20-50 years. Not least the extent and thickness of the Arctic Sea Ice is declining rapidly as well.

Ocean: Melting of ice leads to an accelerated sea level rise. The global sea level rose about 20 cm in the last century, which is a threat for small islands and coastal communities. Increased temperatures also lead to a warming ocean , 0.33°C since the 70’s which along with the increased carbon emissions absorbed by the ocean has caused ocean acidification. This has a critical impact on our marine ecosystems.

Climate Emergency

Even if we limit temperature rise to 1.5°C as proposed in the Paris Agreement, we're still not out of the woods. There are already serious climate impacts at 1.5°C including the complete melting of sea ice in the Arctic Ocean in summer, higher sea levels, the death of over 70% of coral reefs, etc.  Every fraction of additional warming is associated with more devastating impacts. Already at 2.0°C, 99% of coral reefs can be lost, the intensity and frequency of droughts and storms would increase, and the sea level would be 1m higher than at 1.5°C. To prevent warming beyond the 1.5°C, emissions need to be reduced every year to 2030 by 7.6% and with each year we fail to act the cost and difficulty goes up. Given the gravity of the impacts that can already be observed, over 1849 jurisdictions in 33 countries have declared a climate emergency.

The commitments will be reviewed and updated at COP 26 in 2021 and sadly most countries are not on track to fulfill their initial pledges. The United Nations says we could have just 11 years left to limit a climate change catastrophe.

Solution: Climate Mitigation

Climate Mitigation, the human intervention to reduce the sources or enhance the sinks of greenhouse gases, addresses the root cause of the problem rather than its effect. Here are some of the most well-known examples:

• Replacing fossil fuels with renewable energies like solar, wind, hydro and geothermal;
• Replacing internal-combustion vehicles with electric ones;
• Carbon sequestration through forest and ocean preservation, reforestation, etc.
• Rewilding

Climate Adaption is local, with immediate effect and often cheaper, making it the preferred option for many nations. To combat climate change, we need however both types of responses.

Forests

Forests are a well-known carbon sink, vast rainforests such as the Amazon are even referred to as the “lungs of the earth” due to their capacity to trap huge amounts of CO2 and release oxygen. Nearly 25% of the world’s population rely on forests for their livelihoods, they provide vital goods and services such as water and healthy soils and are home to 80% of the world’s terrestrial biodiversity. Currently, they are both a cause and a solution for climate change. About 10% of the global annual emissions are caused by deforestation. However, the remaining forests absorb 2.6 billion tonnes of CO2 yearly. To ensure resilience to climate change we must, on the one hand, combat deforestation and forest degradations and on the other restore forest landscapes.

Coastal and marine ecosystems

Coastal ecosystems, mangroves, tidal marshes and seagrass meadows, known as blue carbon, have only recently been recognised for their significant potential in mitigating climate change. These ecosystems sequester and store more carbon per unit than any terrestrial forest. 83% of the global carbon is circulated through the ocean. Coastal habitats cover less than 2% of the ocean area but account for half of the total carbon sequestered in ocean sediments.

Additionally, these blue carbon habitats provide essential benefits and services such as coastal protection and food security. Tropical coastal ecosystems are also home to 25% of all known marine species, making them biodiversity hotspots. There is the need of better management action, such as the increase of Marine Protected Areas (MPAs) and inclusion of restoration and conservation in national and international climate mitigation plans.

The Greta Effect - What can I personally do about global warming?

"I want you to act as if the house is on fire, because it is."

Greta Thunberg, climate activist

The climate change evidence can seem overwhelming and it can often feel we are too small to achieve change. Don’t get discouraged, here are some things you can do:

• Try to reduce your own carbon footprint – check our carbon calculator and read our guides to find out how you can reduce your emissions and impact on the environment in all the different areas of your life: diet, energy, lifestyle, travel , waste;
• Get political – vote for parties and politicians who prioritise the issue of climate change;
• Take to the streets – join climate activist movements such as Fridays for Future or Extinction Rebellion;
• Be vocal – talk to friends and relatives and share knowledge about these urgent issues;
• Become a Mossy Earth Member: plant native trees every month and contribute to regular rewilding projects;
• Support NGOs and businesses who care about the environment;
• Stay informed – read about the latest climate science.

Multimedia tools to stay updated on climate change

Here are some interactive tools to help you stay updated on climate change and visualise what is happening worldwide:

Vital signs of the Planet – check latest climate change data from NASA, stay updated on the latest measurements for CO2, global temperature, Arctic sea ice minimum, ice sheets and the sea level

Climate vulnerability of your city explore how climate change can affect your city in the next 50 years. This tool, by National Geographic, shows you both the current conditions and the climate outlook in a RCP 8.5 worst-case scenario. It includes information on temperatures, precipitation and extreme weather events

Climate Time Machine – look at these satellite observations and time series on how CO2 levels, global temperature, sea ice and the sea level are changing over time

Images of Change – get interactive before-and-after satellite views of changes occurring in places around the world