Climate change is happening on our planet. Though there are some people who dispute this, in the last 650,000 years. There have been seven cycles of glacial advance and retreat, with the last one being the ice age, that ended around 7000 years ago. This is regarded as the modern era in terms of climate. Most of these changes are thought to have been caused by very minor changes in Earth’s orbit, changing the amount of solar energy that reaches our planet.
The current trend of warming has a 95% probability of being the result of human activity. This has happened mainly since the mid 20th century. Since then the rate of warming is unprecedented in thousands of years.
Global temperature rise
Since the late 19th century Earth’ surface temperature has risen by 1.1°C. This change has been driven by human-made emission into the atmosphere. In the past 35 years, most of the warming has occurred, with 16 out of the last 17 warmest years on record have occurred since 2001. 2016 was the warmest on record and eight of those months were the warmest on record for their respective months.
Evidence shows that our oceans have absorbed much of the heat from global temperature rises. Since 1969 the top 700 of our oceans have warmed by 0.302°F since 1969.
Shrinking Ice Sheets
NASA’s Gravity Recovery and Climate Experiment has observed the Greenland and Antarctic ice sheets. Greenland lost 150 to 250 cubic kilometres (36 to 60 cubic miles) of ice every year between 2002 and 2006. Antarctica lost 152 cubic kilometres (36 cubic miles) of ice between 2002 and 2005.
Globally glaciers are retreating. This trend can be observed in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.
Decreased Snow Cover
Observations of the Northern Hemisphere show that spring snow cover has decreased since the 1970s and that snow is melting earlier in the year.
Rising Sea Levels
Our seas have seen a rise in sea levels of about 8 inches in the past century. In the last two decades, the rate of the rise is double that of the previous century.
Declining Arctic Sea Ice
Both the thickness and coverage of the Arctic sea ice has declined rapidly over the past few decades.
Extreme weather events have been on the rise since 1950. Record high temperatures are common and extreme weather events like tropical storms and hurricanes are on the increase, like Hurricanes Harvey, Irma and Maria, which devastated parts of the USA and the Caribbean. Events like this are due to continue to happen due to global warming.
Since the beginning of the industrial revolution in the late 18th Century, ocean acidity has increased by 30%. This has been caused by carbon dioxide emissions in the atmosphere being absorbed by the oceans. The upper layer of our oceans absorbs roughly 2 billion tons of CO2 a year.