Image capture from NOAA website – Rising sea-levels chart

According to the NOAA (National Oceanic and Atmospheric Organization in the U.S.) there is no doubt the Earth’s climate is warming up. The data the NOAA and other organizations gather, process and combine to produce a time series of global average temperature change provides undisputable proof of a warming trend in global temperatures. This temperature change is then in turn confirmed by other observations of natural phenomena all over the world, such as rising sea levels, earlier blooming of plants in spring, melting glaciers, warming surface temperatures of lakes and reduced arctic ice (just to name a few).

To come to the conclusion that our climate is undergoing a warming trend the NOAA monitors a number of things, what they call the global climate change indicators.

1. Global surface temperatures are rising

The global surface temperature is based on air temperature data over land and sea-surface temperatures. Although fluctuations occur from year to year, over time a global warming trend becomes visible with the 10 warmest years on record all occurring the last twelve years.

2. U.S. surface temperatures are rising

The rising of the global surface temperature is also noticeable within the U.S. This is not inconsistent with expectations from a warming planet.

3. Sea levels are rising

Over the past 100 years sea levels have been rising at a rate of 1,7mm/year. Since 1993 the rate has accelerated to 3,5mm/year. The increasing heat of the oceans is one of the major causes of sea level increase.

4. Ocean temperatures are rising

Ocean waters are warming up. This is also consistent with rising sea levels, causing ocean waters to expand. 2009 was the 4th warmest year on record for ocean waters, after 1988, 2003 and 2005.

5. Annual snow cover in Northern Hemisphere is retreating

The last decennia, annual average snow cover has been on the decline. Since the 70’ spring and summer months where most affected by this warming trend.

6. Glaciers are shrinking

The total volume of glaciers is declining at a fast pace. The shrinking process has been going on for about a century, with a faster decline over the last 10 years. Disappearing glaciers have implications for rising sea levels but also for the availability of water in certain regions like Asia or South America.

7. Extreme climate events are increasing

Over the last 4 decades, extreme climate events (natural disasters) have increased dramatically.

8. Global climate models show human influence on climate change

According to global climate models that observed warming over the last half-century, global warming trends cannot be explained by natural factors alone and are instead caused primarily by human factors.

9. Rising carbon dioxide concentrations in the atmosphere

Over the last 800.000 years CO2 levels in the atmosphere have varied from 170 ppm (parts per million) to 300 ppm. In May of 2010 the CO2 levels reached 392,94 ppm, the highest concentration over the last 800.000 years.

10. Energy from the Sun has not increased

The amount of solar energy that reaches the top of our atmosphere has not increased while global temperatures on Earth are rising. This means that it is extremely unlikely that the Sun would play a part in the global warming trend of the Earth.

For more information about Climate Change or the Global Climate Change Indicators visit the NOAA website.