By AJ Willingham

CNN

(CNN) -- Here's what you need to know to Get Up to Speed and Out the Door.

1. Brexit

Brexit is a go: UK Prime Minister Theresa May will trigger Article 50 today, kick-starting the process that will see Britain leave the European Union in the next two years. How will it affect the UK? The better question is: How won't it? Pro-Brexit politicians have promised a lengthy list of improvements, from new trade deals to huge savings on EU payments. Whether these all pan out remains to be seen.

Meanwhile in Scotland, where Brexit was not very popular at all, lawmakers have voted in favor of a new independence referendum that, if allowed and approved by voters, could break up the UK. Brexit and then ... Scoxit? Yikes.

2. Climate change

President Donald Trump signed a sweeping executive order yesterday that seriously curbs environmental regulations in hopes of producing more jobs. Carbon emissions regulations? Out. Coal mining on federal lands? Back in. The order is essentially a nightmare for scientists and environmentalists, but it's a big fulfillment of one of the President's marquee campaign promises.

Now that some regulations are out the window, the future of world climate change policies could be in the hands of the Chinese. The US and China had a deal that if the US worked on carbon reductions, China would work on curbing greenhouse gas emissions. Now that our promises are off the table, we'll have to see if China keeps fulfilling its own.

3. Mosul

A March 17 airstrike in the Iraqi city resulted in the deaths of at least 112 civilians, and now the top US commander in Iraq says "there's a fair chance" the US was responsible. Both the Iraqi and US defense departments have launched investigations into possible civilian deaths in airstrikes between March 17 and 23. The city of Mosul is ISIS' last major stronghold in Iraq, and US Army Lt. Gen. Stephen Townsend said it is possible ISIS deliberately "lured" US forces to locations where civilian casualties would be high.

4. Health care

Republicans insisted they had no Plan B for their plan to repeal and replace Obamacare. But after that plan was scuttled last week before it could even get a vote, there is, all of a sudden, a Plan B. President Trump, who seemed content to let the Affordable Care Act "explode" and move on to tax reform, told a bipartisan group of senators last night, "I know we're going to make a deal on health care, that's such an easy one."

House Speaker Paul Ryan also said the Republicans would move forward on a new angle. What is it, and when will it happen? "I won't tell you the timeline because we want to get it right," Ryan said.

5. Tennessee kidnapping

The bizarre case of a missing teen and her teacher has a brand new wrinkle: Tennessee's kidnapping law could actually work in the alleged kidnapper's favor. Police are still searching for Elizabeth Thomas and her high school teacher, Tad Cummins, 50, who investigators believe abducted her two weeks ago. However, according to Tennessee law, since Elizabeth is 15, the case would only be "kidnapping" if her flight was "accomplished by force, threat or fraud." Police charges and accounts from the school indicate Elizabeth and Cummins may have been romantically involved.

BREAKFAST BROWSE

People are talking about these. Read up. Join in.

Trump had to turn down offer to throw out first pitch on Opening Day

It's a presidential tradition, so he'd better polish up that four-seamer soon!

Scientists could use stem cells to create an endless supply of blood

Your daily reminder that we are living in the F-U-T-U-R-E.

Pic of undocumented immigrant paying her taxes goes viral

A lot of the comments were ... not nice.

A new app helps you reach your member of Congress

A genius option if, a) the lines are busy; b) you really just hate phone calls.

The 'Fresh Prince of Bel-Air' cast reunited for a fancy photo

It's been 20 years since that show was on the air? How OLD are we?!

NUMBER OF THE DAY

770,000

The number of US drone registrations in the past 15 months. That's a lot of drones!

AND FINALLY ...

This little girl loves her "robot" friend

Absolutely no one is allowed to tell her it's actually a busted water heater.