Scientists are clear about the reality of climate change and we should be too. And with our future at stake, it’s more critical than ever that we support leaders who listen to scientists and are committed to making climate solutions a reality.

The simple fact is that climate change throws natural systems out of balance – to often devastating effect. What does that mean? Let us explain. Here’s a helpful 101-style refresher on climate change.

(With ’round-the-table holiday conversations just down the road, it’s probably worth having your climate talking points in order anyway. You’re welcome!)

Give me the one-sentence pitch on exactly what climate change is (so when my grandpa asks…).



When we talk about climate change, we’re talking about the scientifically observable – and increasingly severe – changes in global climate patterns that became apparent in the mid-to-late twentieth century and can be attributed to the rising levels of atmospheric greenhouse gases (carbon dioxide, in particular) produced by human activities like burning fossil fuels.

That’s a long sentence, we know – but it covers the basics.

Really quick – what’s the difference between weather and climate?



Time, mostly. Weather refers to atmospheric conditions in the short term, including changes in temperature, humidity, precipitation, cloudiness, brightness, wind, and visibility. Climate is the average of weather patterns for a particular region over a longer period of time – typically, 30 or more years.

But scientists don’t agree that climate change is caused by us, right?



Wrong. According to a little organization called NASA, 97 percent of climate scientists agree that global warming over the past century is “extremely likely due to human activities.”

Among climate change deniers’ favorite arguments is that there is not “scientific consensus” that it is man-made. You’ll hear that phrase often, usually alongside talk that the current proven warming trend is part of a natural cycle.

While the Earth has indeed experienced cycles of warming and cooling, scientists estimate that in the past it has typically taken around 5,000 years for the planet to recover – by warming between 4-7 degrees Celsius – after an ice age has ended. This makes the global average surface temperature increase of 1.1—1.6 degrees Fahrenheit (0.6—0.9 degrees Celsius) across just the twentieth century alone roughly eight times faster than the usual post-ice-age-recovery warming rate.

And it’s a cycle that is only accelerating. Fifteen of the 16 hottest years on record globally have occurred this century.

The phrase “scientific consensus” itself refers to the collective judgement of a scientific community, and while it implies agreement, it does not require unanimity. Ninety-seven percent of the climate science community agrees that climate change is real and that it is being caused by human activities such as our use of fossil fuels. Indeed, some scientists have asserted that the evidence linking human activities to climate change is as conclusive as the link between smoking and lung cancer.

Remind me how carbon pollution causes climate change.



When carbon dioxide (CO2) is emitted into our atmosphere, it can hang around for a very long time. The more carbon pollution in the air, the more the sun’s energy gets trapped in our atmosphere as heat. Think about it like this: a build-up of carbon in the atmosphere is acting like a blanket around the Earth. As more heat gets in and less is able to escape, things keep getting hotter and the result impacts every element of our climate system.

Give me two huge effects of climate change that I can easily explain to my mom.



While there are several clear indicators that our climate is changing, the two most likely to get your mom’s attention might be sea-level rise and the increase in severe weather. Unlike many of the more gradual shifts associated with climate change, these are a little less abstract – in many cases, mom can look out her window and see these happening right now.

1.Sea levels are rising



Sea levels have been rising for the past century. And the pace has increased in recent years as glaciers melt faster, Artic sea ice dwindles, and water temperatures increase.

“Flooding will become more frequent as sea level rises,” according to the National Oceanic and Atmospheric Administration (NOAA). “In a sense, today’s flood will become tomorrow’s high tide, as sea level rise will cause flooding to occur more frequently and last for longer durations of time.”

This is happening already in coastal cities in the US. In Florida alone, by the year 2060 (yeah, just 44 years from now), sea levels along the state’s coastline could rise an additional 9 inches to 2 feet. Imagine how similar sea-level rise will affect the almost 40 percent of the US population that lives in a coastal area.

And let’s not forget that eight of the 10 largest cities in the world are near a coast.

2.The weather is getting more severe



Speaking of the coast – do you love the warm water at the beach? So do hurricanes. As worldwide temperatures continue to increase, storms are able to absorb more energy from the resulting warmer oceans. Hurricanes and typhoons can arrive ashore with intense and damaging winds, very heavy rainfall, and major storm surges, often leading to devastating coastal damage and serious loss of life.

As evaporation increases with warmer temperatures, there are some big implications for those further inland, as well.

As the atmosphere gets warmer, it can hold more moisture. This greatly increases the risk of major flooding because, to put it simply, clouds brimming with ever-more evaporated water move over land and burst at the seams.

And it’s not just hurricanes and floods either. Climate change has also been linked to an increase in many other weather extremes, such as heat waves and droughts.

Is it too late to do anything?



Not at all.

It’s true that even if we completely stopped emitting carbon pollution today, we’d continue to experience global warming for a considerable time. The pollution that has caused our current crisis stays in the atmosphere for hundreds of years – so yeah, it’s difficult to stop climate change in its tracks.

But acting now to swiftly transition from dirty fossil fuels to clean energy can limit global warming to no more than 2 degrees Celsius (3.6 degrees Fahrenheit). Two degrees of warming could have significant impacts, there’s no denying. But if we do nothing and continue on the path we’re on, the global average temperature could rise 6 degrees Celsius (10.8 degrees Fahrenheit) by the end of the century. To say the difference between these two scenarios would be dramatic is perhaps quite literally the understatement of the century.

If the global average surface temperature were to increase by 6 degrees Celsius above pre-industrial levels, according to author Mark Lynas (Six Degrees: Our Future on a Hotter Planet):

Most of the planetary surface would be functionally uninhabitable. Agriculture would cease to exist everywhere, apart for the polar and sub-polar regions, and perhaps the mid-latitudes for extremely heat-tolerant crops. … It's pretty much equivalent of a meteorite striking the planet, in terms of the overall impacts.

Seems rough. Seems like the sort of thing we should do everything in our power to avoid, no?

The good news is that we can. And world leaders seem to finally agree that urgent action is a necessity.

But there is a lot of work left to do – work that could easily be disrupted. A bright, sustainable future for our planet is finally in sight, but only if we support leaders who work to make climate solutions a reality. This is where you come in. Join people all around the world in speaking up for clean energy so that when our leaders take action to cut emissions and stop rising global temperatures, we’re with them all the way.

First Name *

Last Name *

Zip * NOT IN THE US? Country * US RESIDENT? Select Country United States Afghanistan Åland Islands Albania Algeria American Samoa Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, The Democratic Republic of The Cook Islands Costa Rica Cote D'ivoire Croatia Cuba Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guam Guatemala Guernsey Guinea Guinea-bissau Guyana Haiti Heard Island and Mcdonald Islands Holy See (Vatican City State) Honduras Hong Kong Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People's Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People's Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, The Former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Marshall Islands Martinique Mauritania Mauritius Mayotte Mexico Micronesia, Federated States of Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands Netherlands Antilles New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Northern Mariana Islands Norway Oman Pakistan Palau Palestinian Territory, Occupied Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Puerto Rico Qatar Reunion Romania Russian Federation Rwanda Saint Helena Saint Kitts and Nevis Saint Lucia Saint Pierre and Miquelon Saint Vincent and The Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and The South Sandwich Islands Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan, Province of China Tajikistan Tanzania, United Republic of Thailand Timor-leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Minor Outlying Islands Uruguay Uzbekistan Vanuatu Venezuela Viet Nam Virgin Islands, British Virgin Islands, U.S. Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Email *



Subscribed Yes, I would like to receive periodic updates and communications from The Climate Reality Project Optional Member Code

